Felix & Co. Accountants

If you’ve earned rental income from a UK residential property and it hasn’t been fully declared to HMRC, you’re not alone — and there’s a structured, HMRC-endorsed way to fix it before it becomes a bigger problem. The Let Property Campaign (LPC) is HMRC’s voluntary disclosure route specifically for landlords, and coming forward through it is almost always cheaper and less stressful than waiting to be found.

With HMRC’s data-matching capability now cross-referencing letting agents, land registries, tenancy deposit schemes, and bank records, the odds of an undisclosed letting going unnoticed are shrinking every year. This guide covers who the campaign is for, what income it covers, the disclosure process step by step, real penalty figures, and the mistakes that most often cost landlords money.

Not sure if the Let Property Campaign applies to your situation? Get a free discovery call with our team and we’ll talk through your exact position.

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What the Let Property Campaign Actually Is

Launched by HMRC in September 2013, the Let Property Campaign gives individual landlords a route to voluntarily correct undeclared or under-declared UK rental income. Landlords who use it before HMRC opens an enquiry can benefit from:

• Meaningfully reduced penalties
• Protection from criminal prosecution in genuine, cooperative cases
• A more efficient, less adversarial resolution than a full compliance check

Why HMRC Runs This Campaign

HMRC’s rationale is straightforward: property income is unusually easy to detect. Letting agent records, land registry filings, council tax data, tenancy deposit scheme registrations, and even bank deposit patterns can all flag an undisclosed letting without the landlord ever coming forward. Add in AI-driven data-matching campaigns targeting Airbnb hosts, agent-managed lettings, and council-tax-registered non-payers, and the picture is clear: HMRC increasingly finds these cases on its own. The campaign exists to reward the landlords who get there first.

The numbers back this up. Over 40,000 disclosures have now been made through the campaign, recovering more than £180 million in previously unpaid tax.

What Income Is Covered Under the LPC

The campaign covers a broad range of residential letting situations, not just traditional buy-to-let. You should be looking at the LPC if any of the following apply to you:

Letting out residential property — a single flat or a full portfolio, whether it came about deliberately or by accident (inheritance, relocation for work), located in the UK or abroad, as long as the income is subject to UK tax.

Short-term and holiday lets — Airbnb income, serviced accommodation, furnished holiday lettings, and any seasonal or short-term letting income.

Rent-a-room and subletting — income from letting a room in your own home once you exceed the £7,500 rent-a-room threshold, or subletting arrangements not already reflected on your return.

Inherited or temporarily let property — a property you’ve inherited and started renting, or letting your own home during a period abroad or a temporary absence.

Previously missed or under reported periods — years where the property was let but the income wasn’t declared, even briefly, or where a return was filed with errors.

Overseas and international lettings — UK residents with rental income from property abroad, and non-UK residents with rental income from UK property.

Who Should Use the LPC

The campaign is designed for landlords who:

• Have rental income that’s never been declared to HMRC
• Made errors on previous returns — under reported income, over-claimed expenses
• Didn’t realise rental income needed reporting at all, regardless of whether it generated a profit

One point catches a lot of landlords out: even if allowable expenses wipe out your taxable profit entirely, you’re still legally required to report the income and expenses. Making no profit is not the same as having nothing to declare.

Common real-world scenarios

• Inheriting a parent’s home and renting it out without telling HMRC
• Becoming a landlord while working abroad, letting your UK home without realising it still needs reporting
• Renting a spare room informally, assuming the amount is too small to matter
• Moving in with a partner and letting your previous home without updating HMRC
• Assuming a letting agent was handling the tax reporting (HMRC holds the landlord personally responsible, not the agent)
• Misapplying mortgage interest relief rules, particularly following the 2020 change to a 20% tax credit
• Jointly owned property where reporting responsibilities weren’t clearly split between owners

Who’s Eligible — and Who Isn’t

You’re eligible if you’re:

• An individual (not a company, trust, or partnership)
• Earning income from UK residential letting — including buy-to-let, Airbnb, accidental landlord situations, and non-resident landlords with UK property
• Willing to disclose fully and voluntarily, before HMRC has opened an enquiry — meaning a complete declaration of all under-reported income, full transparency on years and documentation, and a genuine willingness to resolve what’s owed

You’re excluded if:

• HMRC has already opened a compliance check or raised questions about your rental income — in this case you must respond directly to that enquiry instead
• Your income comes from non-residential property (offices, shops, industrial units) — the LPC covers residential letting only
• You’re a company, trust, or partnership, which need to use a different HMRC disclosure route

Worth noting: if you hold a mixed portfolio, only the residential portion qualifies for LPC — commercial property needs separate arrangements. Joint owners each need to make their own individual disclosure for their share of the income, and non-UK residents with UK rental income remain eligible if they meet the other criteria.

The Disclosure Process, Step by Step

1. Register your intent with HMRC Access the LPC service on GOV.UK and submit your details, including your National Insurance number, through the Digital Disclosure Service (DDS). HMRC issues a Disclosure Reference Number (DRN) and Payment Reference Number (PRN) — keep both, as they’re needed throughout.

2. Gather your information Pull together rental income figures for every relevant year, including years spent abroad or where the property stood empty part-time. Supporting documents matter here — tenancy agreements, mortgage interest records, utility bills, maintenance invoices, council tax records, and bank statements.

3. Calculate what’s owed Work out gross rental income, allowable expenses, and any capital allowances. HMRC’s online calculators can help, though complex cases usually benefit from a tax advisor. Don’t forget interest on the late tax — and be aware that penalties will be set according to your behaviour category (careless, deliberate, or concealed).

4. Submit your disclosure Complete the full disclosure through the DDS portal, explaining clearly why the errors or omissions occurred and what you’ve done to correct them. You have 90 days from receiving your DRN to submit.

5. Pay what’s due Once you’ve registered your intent, you’ll receive a payment reference to settle the total tax, interest, and penalty — either in full or through an agreed payment arrangement discussed directly with HMRC beforehand.

6. Confirmation and closure HMRC reviews the disclosure; honest, thorough submissions tend to close fastest. If further information is needed, respond promptly. Once accepted, HMRC issues a closing letter confirming the total amount payable, the period covered, any payment arrangement, and that the case is closed provided the terms are met.

Staying Compliant After Your Disclosure

Closing an LPC case isn’t the end of the story. Going forward, you’ll need to:

• Declare all rental income and expenses on your annual Self Assessment return, regardless of profit or loss
• Keep organised records for at least six years — receipts, agreements, correspondence — in case HMRC requests them later
• File and pay by the 31 January deadline each year to avoid fresh penalties and interest
• Stay current with HMRC guidance, since rules on allowable expenses and digital filing do change — HMRC’s Property Rental Toolkit is a useful reference
• Revisit your position with a tax advisor whenever circumstances shift — new properties, overseas lettings, changes in tax residency

Our tax-saving strategies guide is a good next step once you’re back in good standing, for legitimate ways to manage the ongoing liability.

Real Disclosure Examples

The accidental landlord. Emma inherited her mother’s flat and let it out from 2018 without informing HMRC. Realising the gap in 2025, she disclosed £6,000 of undeclared rent through the LPC and, because she came forward voluntarily, paid only a 10% penalty with no further action.

The overseas landlord. Ajay relocated to Spain for work and let out his former UK home, unaware of his ongoing UK tax obligations as a non-resident. After receiving a nudge letter from HMRC, he used the LPC — working with a tax advisor to declare five years of rental profit — and secured a low penalty rate.

The inherited property. James inherited a house in 2017, let it out, and only recognised the reporting requirement in 2025. He used the LPC to settle seven years of unpaid tax plus interest, with a 15% penalty.

For a deeper look at how the maths plays out with real figures, our article on Let Property Campaign voluntary disclosure walks through two full case studies comparing voluntary versus prompted disclosure costs.

How Long Does a Disclosure Take?

Most LPC disclosures run 12–16 weeks from initial registration to final resolution, covering preparation, submission, and any follow-up queries or payment arrangements. Complex cases or gaps in documentation can extend this considerably.

Are LPC Cases Increasing?

Yes. In 2023, HMRC flagged over 18,000 property-related cases for compliance review — a figure expected to keep climbing as digital data-matching against letting agent returns, land records, and banking data becomes more sophisticated. The wider the net gets, the more voluntary, proactive disclosure makes financial sense.

How Penalties Are Actually Calculated

Penalties depend on several factors working together: the nature of the error (careless, deliberate, or deliberate and concealed), whether the disclosure was unprompted or prompted by HMRC contact, how long the omission persisted, and the quality of your cooperation.

There are two broad scenarios that trigger penalties — failure to notify HMRC of taxable income at all, and inaccurate returns where income was filed but understated. Both are calculated as a percentage of the additional tax owed (the “Potential Lost Revenue”), and a high-quality disclosure can cut that percentage by up to 90% within its range.

Voluntary, honest disclosure typically sits in the 0–20% penalty range — the lowest available — provided you’re fully cooperative, prompt, and transparent.

Prompted disclosure, where HMRC contacts you first, loses access to that leniency: rates run higher, sometimes double the voluntary range, even with full cooperation afterwards.

Deliberate or concealed behaviour carries the steepest penalties, typically 35–100% of the tax owed, and in the most serious cases can lead to criminal prosecution.

Reasonable care cases — genuine mistakes made despite taking sensible steps to get things right — can, in some circumstances, see the penalty waived entirely.

Key Takeaways

• Voluntary disclosure before HMRC makes contact consistently produces the lowest penalty range, typically 0–20% of the tax owed
• The quality of your disclosure — being open, prompt, and thorough — drives further reductions within that range
• Genuine mistakes made with reasonable care can sometimes avoid a penalty altogether
• Deliberate concealment carries the harshest consequences, both financially and legally
• Professional guidance consistently improves outcomes — accurate figures, complete documentation, and a well-presented case all reduce the eventual penalty

Common Mistakes to Avoid

Only declaring recent years. HMRC can require disclosure going back up to 20 years for deliberate or concealed errors — review every year with missing or inaccurate figures, not just the obvious ones.

Misclassifying allowable expenses. Since April 2020, mortgage interest relief works as a 20% tax credit rather than a straight deduction — a common source of error.

Leaving out overseas property. Worldwide rental income is re-portable if you’re UK tax resident, not just UK-based lettings.

Doing the calculations yourself. Self-calculated figures frequently miss reliefs or misstate the tax owed — a second set of eyes from a qualified accountant catches this before HMRC does.

Missing the 90-day window. Once you’ve registered, the clock is running — late submission can forfeit the penalty reductions you’d otherwise qualify for.

Assuming the letting agent handles it. The legal responsibility for reporting sits with the landlord, regardless of what an agent manages day to day.

Assuming no profit means nothing to declare. All rental income needs reporting even where allowable expenses bring the taxable profit to zero.

Waiting to be contacted. A disclosure made after a nudge letter is a prompted disclosure — and loses the best penalty terms by definition.

Incomplete documentation. Missing tenancy agreements or bank statements can stall a disclosure or undermine its credibility — keep thorough records for every property and year involved.

When to Bring In Professional Help

Certain situations tend to benefit most from specialist advice:

• More than four years of undeclared income, where the calculations and documentation requirements get more complex
• Multiple properties or overseas lettings, which can introduce double taxation questions and varying expense rules
• Complicated expense positions — joint ownership, furnished holiday lettings, or major repair and improvement claims

As one chartered tax advisor puts it, the Let Property Campaign is a genuine opportunity to regularise your affairs on favourable terms — provided the disclosure is accurate and the communication with HMRC stays open throughout.

Frequently Asked Questions

Do I need to use the LPC if I’ve already reported my rental income? No — the campaign is specifically for correcting income that wasn’t declared, or was declared incorrectly. If your returns are already accurate, there’s nothing to disclose.

Who can use the LPC? Individual landlords — not companies, trusts, or partnerships — with undeclared or under-declared UK residential rental income, whether they’re UK resident or overseas.

What happens if HMRC contacts me first? You move from a voluntary to a prompted disclosure, which carries higher penalty rates and less flexibility, though cooperation still helps.

What if I can’t afford to pay what’s owed right now? Contact HMRC’s LPC helpline before submitting your disclosure or any payment — they can discuss a realistic payment arrangement based on your financial position.

What expenses can I claim against my rental income? Allowable expenses generally include letting agent fees, repairs and maintenance, insurance, and a mortgage interest tax credit (since the 2020 rule change) — a tax advisor can confirm what applies to your specific setup.

How many years do I need to disclose? It depends on why the income wasn’t declared — careless errors typically mean up to six years, deliberate or concealed behaviour can extend that to twenty. Our guide on which years to declare breaks this down in detail.

Will I be prosecuted? Prosecution is reserved for the most serious, deliberate, and concealed cases. Honest, cooperative voluntary disclosures are very rarely treated this way.

Quick Reference Tips

• Joint landlords each need to submit their own individual disclosure
• Overseas landlords should check whether double taxation arrangements apply to their situation
• Keep documentation for at least six years after your disclosure is closed
• If older records genuinely don’t exist, explain this within the disclosure — HMRC will generally work from a reasonable best estimate
• Get advice from a specialist tax advisor if your case involves overseas property, joint ownership, or inheritance complexities

Final Thoughts

The Let Property Campaign remains one of the most practical routes HMRC offers landlords to put things right. With data-matching only getting sharper, waiting to be contacted is the more expensive option in almost every case. Whether your situation started as an honest oversight, a life event like an inheritance, or something more complicated, coming forward on your own terms keeps you in control of the outcome.

Ready to work out exactly where you stand?

👉 Book a free discovery call

An HMRC letter about rental income deserves attention, but the first step is to find out exactly what it is asking you to do. Some letters invite you to check your records; others may form part of a formal enquiry. Read the response instructions and dates before deciding how to proceed. The Let Property Campaign gives individual landlords a structured route to put things right, with a clear 90-day window to work out and pay what’s owed.

An HMRC letter about rental income deserves attention, but the first step is to find out exactly what it is asking you to do. Some letters invite you to check your records; others may form part of a formal enquiry. Read the response instructions and dates before deciding how to proceed.

Doing It Yourself vs Using an Agent

An HMRC letter about rental income deserves attention, but the first step is to find out exactly what it is asking you to do. Some letters invite you to check your records; others may form part of a formal enquiry. Read the response instructions and dates before deciding how to proceed.

Step 1: Notify HMRC of Your Intention to Disclose

If your review confirms unpaid tax and the Let Property Campaign is available for your circumstances, notify HMRC of your intention to disclose. At notification stage, you do not need the full calculation. If an enquiry has already been opened, check the correct route with HMRC or your adviser.

Once submitted, HMRC issues a unique Disclosure Reference Number (DRN) — this becomes your reference for all further correspondence — along with a Payment Reference Number to settle the eventual liability.

One detail catches out a lot of joint owners: each person must notify and disclose separately. If a rental property is jointly owned by a married couple, for example, both need to submit their own individual notification and disclosure covering their own share of the income — a single combined submission on behalf of both isn’t accepted.

Step 2: Disclose Your Undeclared Income — Within 90 Days

For an eligible Let Property Campaign disclosure, HMRC says the 90-day period runs from receipt of the notification acknowledgement. Prepare the relevant calculations and check the actual deadline shown in the acknowledgement. Payment is normally due when you disclose unless you have agreed another arrangement with HMRC.

If you genuinely can’t pay everything by the deadline, the fix isn’t to delay the disclosure — it’s to contact HMRC before the deadline to arrange a payment plan. Missing the payment and notification deadline together is what turns a manageable situation into a more difficult one, so treat both dates as fixed.

How Far Back Does Your Disclosure Need to Go?

This is usually the question landlords care about most, and the honest answer is: it depends on why the income wasn’t reported in the first place. Landlords are required to notify HMRC of letting income by 5 October following the end of the relevant tax year — for 2023/24 income, that’s 5 October 2024, with the Self Assessment return itself due by 31 January 2025. Miss those, and the look-back period is set by which of the following applies to your situation.

You took reasonable care

If you were registered for Self Assessment on time and made genuine efforts to keep your affairs in order, but still ended up underpaying, HMRC will generally only ask you to settle up to four years. Staying compliant from here means:

• Filing accurate, on-time returns for the current and future years
• Reporting any outstanding tax from the prior year in the correct return, by deadline
• Completing your disclosure and payment for the three tax years before that

You didn’t take reasonable care

Where you registered on time but ended up underpaying through carelessness — rather than a genuine, well-intentioned mistake — the look-back period extends to a maximum of six years. That means:

• Accurately reporting the current and future tax years by their deadlines
• Correctly reporting the year immediately before the current one, on the return issued for it
• Completing the disclosure and settling what’s owed for the five years before that

You deliberately misled HMRC

For an eligible Let Property Campaign disclosure, HMRC says the 90-day period runs from receipt of the notification acknowledgement. Prepare the relevant calculations and check the actual deadline shown in the acknowledgement. Payment is normally due when you disclose unless you have agreed another arrangement with HMRC. HMRC’s default expectation is a six-year disclosure for most landlords — the twenty-year extension is reserved specifically for cases involving deliberate misstatement or a complete failure to disclose. For a deeper breakdown of how this behaviour classification actually works in practice, our guide on which years you need to declare covers it in full.

Why Acting Before the Letter Arrives Is Still Worth Doing

If you have not heard from HMRC but believe rental tax has been underpaid, consider putting the position right promptly. The availability of the Let Property Campaign and any penalty treatment depend on the facts. The key is to make an accurate complete disclosure rather than wait for contact. our voluntary disclosure guide sets out exactly what that penalty difference looks like in practice, with real worked examples.

First 15 minutes: check the letter, not your assumptions

Keep the envelope and every page of the letter, including any forms or reference numbers. Note the date, the tax years mentioned, the department writing to you and what HMRC has actually requested. Look for any deadline, but do not assume every letter carries the same response period. If you are unsure whether it is genuine, use GOV.UK’s guidance on checking HMRC correspondence and contact HMRC through independently verified details.

Do not supply bank information or click a link merely because it appears in an unexpected message. Once the letter is verified, make a short list of what you know, what still needs checking and what you may have already reported. This gives you a sensible basis for deciding whether a reply, amended return, disclosure or professional review is necessary.

Putting It All Together

A letter from HMRC is a prompt, not a verdict — the outcome still depends heavily on how quickly and accurately you respond. Notify promptly, gather the right documentation for the years that matter, and get the behaviour classification right before you submit, since that single judgement call affects both how many years you’re disclosing and what penalty rate applies. For the complete picture on eligibility, process, and worked examples, our Let Property Campaign guide brings everything together in one place.

FAQs

Does receiving an HMRC letter mean I have tax to pay?

No. A letter may be based on information HMRC wants you to review, and there may be a reasonable explanation. For example, rent might have been reported on a return, a property could be jointly owned, or the tax position may differ from what HMRC initially assumes. Equally, an explanation should be supported by documents rather than guesswork. Compare the dates of letting, gross rent, claimed expenses and previous tax returns before deciding what to say. If tax was omitted, identify which years are affected and whether a tax return or a formal disclosure is the correct route.

What if I cannot pay all the rental tax now?

If you believe tax is due but cannot pay the full amount, do not ignore the problem or simply miss the deadline. HMRC’s Let Property Campaign guidance says you should contact the campaign helpline before submitting the disclosure if full payment is not possible. Be ready to explain your income, regular outgoings, assets, other debts and how you propose to pay. HMRC can then consider whether a payment arrangement is possible. The disclosure itself still needs to be accurate and you must follow the deadline stated in HMRC’s acknowledgement or other correspondence

Got a letter and not sure where to start? Book a free discovery call and we’ll help you respond correctly, within the deadline.

Book your free discovery call

Let Property Campaign: Know the Years You Need to Declare

If you’re a landlord who has discovered that rental income wasn’t reported correctly to HMRC, the first question is rarely “how much tax do I owe?” It’s “how far back does this go?”

That question trips up more landlords than almost any other part of the Let Property Campaign. There’s no single, universal answer — HMRC doesn’t apply a flat six-year rule to everyone. Instead, the number of tax years you’re required to disclose depends on why the income went unreported in the first place. Get that wrong, and you risk an incomplete disclosure, a challenge from HMRC, and additional penalties further down the line.

This guide walks through exactly how the look-back period is calculated, how HMRC’s three behaviour categories work, and the mistakes that most commonly catch landlords out.

Not sure where your disclosure should start? Book a free, no-obligation discovery call with our Let Property Campaign specialists and we’ll help you work out exactly which years apply to your situation.

👉 Book your free discovery call

Who the Let Property Campaign Is For

The Let Property Campaign is HMRC’s voluntary disclosure route for landlords whose rental income hasn’t been reported correctly — whether that’s income left off a return entirely, or a return filed with the wrong figures.

It’s built around individual landlords rather than corporate structures, and it covers a wide range of situations:

• Landlords with a single rental property who never registered for Self Assessment
• Portfolio landlords who missed one property among several
• UK residents letting property overseas, and overseas residents letting UK property
• Short-term lets that were sold before the income was ever declared
• Landlords already in Self Assessment whose figures were wrong

There’s no minimum threshold. HMRC’s own guidance treats the campaign as open to anyone with undeclared or under-declared rental income, regardless of how small the sums involved. For a broader look at how UK rental income is taxed in the first place, our property tax guide covers the basics landlords are expected to know.

What the Campaign Does — and Doesn’t — Change

It’s worth being clear-eyed about what the Let Property Campaign actually offers.

It gives you a structured way to:

• Come forward before HMRC finds the issue independently
• Calculate and settle tax, interest, and penalties yourself, with HMRC’s oversight
• Generally receive more favourable treatment than if HMRC uncovers the problem through a compliance check

It does not:

• Cap or reduce HMRC’s legal power to assess tax
• Let you pick a convenient disclosure period
• Guarantee lower penalties automatically — that still depends on how the disclosure is made and how complete it is

In short, coming forward voluntarily is the advantage. The scope of what you need to disclose is still governed entirely by HMRC’s rules, not by your preference.

Why “Behaviour” Is the Deciding Factor

Here’s the part that catches people out: the number of years you must go back is not fixed. It’s determined by HMRC’s assessment of why the tax went unpaid — referred to as your “behaviour.”

This matters for a legal reason, not just a moral one. The standard assessment window is limited, but HMRC can extend it — to six years or even twenty — only where specific statutory conditions are met. Those conditions hinge on whether the loss of tax resulted from carelessness or from a deliberate decision not to declare.

Get the behaviour classification wrong on your disclosure, and HMRC can challenge it later — reopening a case you thought was closed.

Careless behaviour → normally up to 6 tax years

This applies where reasonable care wasn’t taken, but there was no intent to avoid tax. Typical examples include:

• Not realising rental income needed declaring at all
• Misapplying the rules on allowable expenses
• Errors on a return that went unchecked

HMRC assesses “reasonable care” against what a sensible, prudent person in the landlord’s position would have done. Using an accountant is actually meaningful evidence here — it can support the argument that reasonable care was taken, even if a mistake still occurred.

Example: A landlord claims expenses that turn out not to be allowable, purely from misunderstanding the rules, and it’s picked up years later. This typically results in a six-year disclosure.

Deliberate behaviour → up to 20 tax years

This is where rental income was left out knowingly — not through misunderstanding, but by choice. Examples include:

• Receiving rent and simply not declaring it
• Knowing tax registration was required and not doing it
• Repeated, ongoing omission of rental income from returns

Example: A landlord has let a property since 2010 and knowingly never registered for tax on the income. Because the letting activity — and the unpaid tax — started in 2010/11, that’s where the disclosure begins, not an arbitrary twenty years prior.

Deliberate and concealed behaviour → up to 20 tax years, with heavier penalties

The most serious category applies where income wasn’t just omitted, but active steps were taken to hide it — for example, rent paid into an account not linked to the landlord’s name, no records kept at all, or misleading information given if questioned. The look-back period mirrors deliberate behaviour, but penalties sit at the top end of the scale.

How Behaviour Affects Penalties and Interest

Behaviour doesn’t only decide how far back you go — it drives the penalty range too. Careless errors sit at the lower end; deliberate and concealed behaviour at the top. On top of any penalty, interest accrues separately on the unpaid tax from the original due date until it’s settled, regardless of category.

This is why correctly identifying — and being able to justify — your behaviour category matters as much as the arithmetic. Landlords weighing up how to minimise the overall cost of a disclosure may also find it useful to look at our guide to tax-saving strategies for legitimate ways to manage the ongoing liability once matters are up to date.

Working Out Which Years Actually Belong in Your Disclosure

Once you know your behaviour category, the next step is translating that into an actual list of tax years. This isn’t a matter of picking a convenient starting point — it follows a specific logic.

1. Start with the most recent tax year. If a return is already due for the latest year, that’s usually handled through normal Self Assessment rather than folded into the historic disclosure — the Let Property Campaign is then used to correct everything before it.

2. Count backwards using your behaviour category. Up to six years for careless behaviour, up to twenty for deliberate or concealed behaviour — but only as far as there was genuine letting activity and unpaid tax. If the property wasn’t let, or there was no under-declared income, in an earlier year, that year simply isn’t part of the disclosure.

3. Confirm each year actually generated a tax liability. More on this below — not every year within the look-back window needs to be included.

Careless example: An error identified in 2025 typically means reviewing 2019/20 through 2024/25 — the six most recent tax years — and including only the ones with genuine underpaid tax.

Deliberate example: Letting began in 2010/11 and income was knowingly withheld. Because that’s when the tax loss started, the disclosure runs from 2010/11 forward — not from an earlier, arbitrary date.

When Your Behaviour Isn’t Consistent Throughout

It’s common for a landlord’s situation to shift over time — genuine confusion in the early years, followed later by a conscious decision not to declare once the rules became clear.

Where that happens, HMRC applies the most serious behaviour identified across the whole period when deciding how far back it can assess. A change from careless to deliberate partway through can therefore extend the maximum look-back significantly — even though the earliest years were a genuine mistake.

Example: A landlord starts letting in 2014/15 and doesn’t realise the income is taxable until 2018/19, from which point they’re aware but continue not declaring. The later deliberate conduct means HMRC can, in principle, assess up to twenty years — but because letting only began in 2014/15, that’s still the actual start of the disclosure.

Do You Have to Include Years With No Tax Due?

Not automatically. If, after allowable expenses, a year produced a loss rather than a profit, HMRC’s guidance says that year doesn’t need to be included in the disclosure figures — because no tax was underpaid.

That doesn’t mean loss years are irrelevant, though. Rental losses can be carried forward against future profits, so it’s worth keeping the calculations and supporting evidence for those years even if they’re excluded from the disclosure itself.

Low rental income is a different matter from a loss. If a year generated modest income but tax was still underpaid, that year belongs in the disclosure — the test is whether tax was due, not how much income there was.

Missing or Incomplete Records

Gaps in your paperwork are common, especially for lettings going back a decade or more — and they don’t remove the obligation to disclose. HMRC expects a reasonable, honestly reconstructed estimate rather than perfect records.

In practice, that usually means piecing figures together from:

• Bank statements showing rental receipts and related payments
• Letting agent statements or tenancy agreements
• Surviving invoices, or realistic estimates based on the type of property and period involved

The estimate needs to be consistent and defensible — inflating costs or understating income to fill gaps undermines the whole disclosure. Where records genuinely don’t exist, say so plainly as part of the submission; HMRC’s guidance acknowledges this happens and expects a fair attempt, not certainty.

Mistakes Landlords Commonly Make With Disclosure Years

Most problems with Let Property Campaign disclosures come down to a handful of recurring errors:

• Assuming a flat six-year rule applies to everyone, regardless of behaviour
• Excluding a low-income year that still owed tax, confusing “small” with “no liability”
• Understating earlier behaviour as careless when it later became deliberate, risking a challenge and an extended look-back
• Overlooking a whole property or letting period — a short let, an informally rented room, or overseas income that got missed
• Delaying the disclosure because records are incomplete, when a reasonable estimate would have been accepted

Each of these can slow the process down or trigger further HMRC questions, so it’s worth getting the classification and the years right before you submit rather than after.

Frequently Asked Questions

Does HMRC always go back six years? No. Six years applies to careless behaviour. Deliberate or concealed behaviour can extend the look-back to twenty years.

Can I leave out a year because I don’t have full records? No — missing records don’t remove the obligation to disclose. A reasonable, well-explained estimate is expected instead.

Do I need to include a year where the property made a loss? Generally no, if no tax was actually due for that year. Keep the figures anyway, since losses can carry forward.

What if my reason for not declaring changed over time? HMRC applies the most serious behaviour identified across the whole period, which can extend the maximum assessable years even if the issue started as a genuine mistake.

Getting Local, Specialist Help

Because the correct disclosure period depends so heavily on the specific facts of your case, generic guidance can only take you so far. Our Let Property Campaign specialists work with landlords across the UK, including in:

• Oxford
• Windsor
• London
• Reading
• Slough

Summary

The number of years you need to disclose under the Let Property Campaign comes down to why the income wasn’t declared correctly — not a fixed rule. Careless errors typically mean a six-year look-back; knowingly withheld income can extend that to twenty. Within that window, only years with genuine letting activity and underpaid tax need to be included, and incomplete records are addressed with reasonable estimates rather than used as a reason to delay.

Getting the years — and the behaviour classification behind them — right the first time is what keeps a disclosure from being challenged or extended later.

Ready to find out exactly which years apply to you?

👉 Book a free discovery call.