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If you have received rental income from a property but have not declared it to HMRC, you might be worried about what could happen next. Perhaps you have been renting out a property for several years, recently inherited a house, or simply did not realise that rental income needed to be reported on a Self Assessment tax return.

The good news is that HMRC provides a voluntary disclosure route specifically for landlords who have failed to declare rental income. It is called the Let Property Campaign, and it gives eligible landlords an opportunity to bring their tax affairs up to date, pay the tax they owe and potentially receive lower penalties than they might face if HMRC discovers the undeclared income first.

Understanding how the Let Property Campaign works is important because making a disclosure involves more than simply adding up rental income and paying an outstanding tax bill. You need to establish which tax years are involved, calculate allowable expenses, work out the correct tax and interest, and determine the appropriate penalty.

This guide explains the process in straightforward terms, including how to prepare a disclosure, use a calculator, understand penalties and decide whether professional accounting assistance would be worthwhile.

Table of Contents

1. Let Property Campaign
2. Let Property Campaign Disclosure
3. Let Property Campaign Calculator
4. Let Property Campaign Accountant
5. How to make a voluntary disclosure
6. Conclusion

Let Property Campaign

The Let Property Campaign is an HMRC disclosure opportunity designed to help individual landlords who have not declared rental income correctly in previous tax years.

It is particularly useful for people who have rented out residential property without realising that they needed to register for Self Assessment or report their rental profits to HMRC.

Who can use the Let Property Campaign?

The campaign is available to individual landlords with undeclared rental income from residential property in the UK or abroad.

You may be eligible if you:

• Have rented out a house or flat but never declared the rental income.
• Have several rental properties and failed to report income from one or more of them.
• Have inherited a property and subsequently rented it out without declaring the income.
• Have rented out a room in your own home and exceeded the Rent a Room Scheme threshold.
• Have received income from holiday lettings.
• Live abroad but receive rental income from a property in the UK.

However, the campaign is not available to everyone.

For example, it does not cover companies or trusts that own rental properties, or landlords who only rent out commercial properties such as shops, garages or business premises.

If you operate a property business through a limited company, you will need to consider the appropriate HMRC disclosure route instead.

Why should landlords make a voluntary disclosure?

HMRC receives information from various sources, including financial institutions, letting agents and other organisations. It may also receive information about property ownership and rental activity from overseas tax authorities.

If HMRC discovers that you have failed to declare rental income, it can investigate your tax affairs and charge the outstanding tax, interest and penalties.

Coming forward voluntarily can result in substantially lower penalties, particularly where the disclosure is unprompted and you provide HMRC with accurate information.

There is also the advantage of resolving the problem before HMRC starts an investigation.

How far back can HMRC investigate undeclared rental income?

The number of years you need to disclose depends on why the income was not declared and whether you took reasonable care with your tax affairs.

HMRC generally applies the following time limits:

Circumstances	Maximum assessment period
Error despite reasonable care	4 years
Careless error	6 years
Deliberate failure to declare income	20 years

These are maximum periods, not automatic rules that apply identically to every case.

For example, if a landlord registered for Self Assessment but accidentally omitted rental income from their tax return, HMRC may consider whether reasonable care was taken or whether the omission was careless.

However, someone who deliberately concealed rental income could face a much longer assessment period.

The starting point is understanding what happened, when the landlord should have notified HMRC and whether the failure was careless or deliberate.

Which tax years should be included in a disclosure?

The tax year in which you are making your disclosure is important.

As this article is being written in November 2026, the current tax year is 2026/27.

Under HMRC’s current guidance, income from the current tax year and the preceding tax year should normally be dealt with through Self Assessment rather than the Let Property Campaign.

For example:

• 2026/27: Report through the appropriate Self Assessment process.
• 2025/26: Report through the 2025/26 tax return.
• Earlier tax years: Consider including them in the Let Property Campaign, depending on the circumstances and applicable time limits.

There is an additional consideration where HMRC has already issued a Self Assessment tax return for an outstanding year from 2022/23 onwards. HMRC’s guidance says that these outstanding returns must be completed rather than including those years in the campaign disclosure.

This is particularly important because registering for Self Assessment can sometimes result in HMRC automatically issuing tax returns for outstanding years.

You should check the position before preparing the disclosure rather than assuming every previous year belongs in the campaign.

Official guidance: HMRC – Let Property Campaign: Your guide to making a disclosure.

Let Property Campaign Disclosure

A Let Property Campaign disclosure is the formal process of telling HMRC about rental income that you have not previously declared and calculating the tax, interest and penalties that you need to pay.

It is not simply a letter explaining that you forgot to declare rental income. You must provide HMRC with a complete calculation and a formal offer to settle your outstanding liabilities.

There are several stages involved.

Step 1: Notify HMRC that you intend to make a disclosure

Before submitting your calculations, you need to notify HMRC that you intend to use the Let Property Campaign.

This is done through HMRC’s Digital Disclosure Service.

At this stage, you are not required to provide a full breakdown of your rental income or calculate your outstanding tax.

You are simply informing HMRC that you intend to make a disclosure.

Once HMRC processes your notification, it will provide a unique Disclosure Reference Number (DRN). You will also receive a payment reference number.

Keep these references safe because you will need them when communicating with HMRC and making your payment.

If an accountant or tax adviser is handling the disclosure, they can notify HMRC on your behalf using the appropriate agent service.

Step 2: Gather your rental income records

Once you receive your reference number, you can start preparing the disclosure.

You should collect as much information as possible for every relevant tax year.

Useful records include:

• Bank statements showing rental payments.
• Tenancy agreements.
• Statements from letting agents.
• Mortgage interest statements.
• Receipts for repairs and maintenance.
• Insurance bills.
• Ground rent and service charge statements.
• Council tax and utility bills, where applicable.
• Records of any previous tax returns.

Ideally, you should prepare a separate income and expense calculation for each tax year.

For example, imagine a landlord rented out a property between April 2020 and April 2026. They should establish how much rent they received in each tax year rather than calculating one total amount for the entire period.

This matters because tax rates, personal allowances and other relevant rules can change between tax years.

What if you no longer have all your records?

Not having complete paperwork does not necessarily prevent you from making a disclosure.

HMRC says that where records are incomplete, you should make your best estimate of the undeclared income and gains.

However, you should keep evidence explaining how you arrived at your figures. Bank statements, letting agent records and historical rental agreements can help support your calculations.

Step 3: Calculate your rental profits

You need to establish the taxable rental profit for each relevant year.

The basic calculation is:

Rental profit calculation

Gross rental income

£15,000

Allowable expenses

£3,000

Taxable rental profit

£12,000

Illustrative example, assuming no other adjustments or losses.

Allowable expenses can include:

• Property insurance.
• Repairs and maintenance.
• Letting agent fees.
• Accountancy fees relating to the rental business.
• Ground rent and service charges.
• Certain legal and professional fees.
• Other qualifying costs of managing and maintaining the property.

However, not every property-related payment is deductible.

For example, improvements that increase the value of a property are generally capital expenditure rather than ordinary rental expenses.

Mortgage interest also needs special attention. Individual residential landlords generally cannot deduct the full mortgage interest as an expense. Instead, they may receive a basic-rate tax reduction under the residential finance cost rules.

The £1,000 property allowance may also be relevant for certain tax years, but it should not be applied indiscriminately. It was introduced for 2017/18, so it is not available for earlier years.

For more information about allowable costs, see our guide to landlord expenses in the UK.

Step 4: Calculate the additional Income Tax

After calculating the rental profit, you need to work out how much additional Income Tax should have been paid.

This is not necessarily a simple calculation using the basic-rate tax percentage.

Your rental profit is added to your other taxable income for the relevant tax year. This means that the amount of additional tax depends on your employment income, pension income, other taxable income and available allowances.

For example, consider someone who earns £30,000 from employment and has an additional £12,000 rental profit.

Their total income before considering allowances and other adjustments is £42,000.

The rental profit may therefore be taxed partly or entirely at the basic rate, depending on their circumstances and the tax rules for that particular year.

Now consider someone earning £48,000 from employment with the same £12,000 rental profit.

Their additional rental income could push some of their income into the higher-rate tax band.

You must calculate the additional tax for each year using the relevant historical tax rates and allowances.

Do not simply multiply all your undeclared rental profits by today’s tax rate.

Step 5: Calculate interest and penalties

After establishing the additional tax, you need to calculate the interest and any applicable penalties.

Interest is charged on unpaid tax from the date it was originally due until the date it is paid.

Penalties depend on the circumstances surrounding the original failure.

For example, HMRC considers:

• Whether the failure was careless or deliberate.
• Whether the disclosure is unprompted or prompted.
• How much assistance you provide to HMRC.
• How quickly you came forward after discovering the error.
• Whether you provide a complete and accurate disclosure.

These factors can have a substantial impact on the final amount payable.

Step 6: Submit your disclosure and payment

Once you have completed your calculations, you can submit your disclosure to HMRC.

You must provide the required information, calculate your liabilities, include the appropriate penalties and interest, and make a formal offer to settle the outstanding amount.

HMRC normally gives you 90 days from the date of your notification acknowledgement to submit the disclosure and payment.

If you cannot pay the full amount, you should contact HMRC before submitting the disclosure to discuss a possible payment arrangement.

Do not simply submit an incomplete disclosure and assume you can arrange payment afterwards.

HMRC expects you to meet the deadline or agree suitable arrangements before it expires.

Let Property Campaign Calculator

A Let Property Campaign calculator can help landlords estimate how much they owe HMRC, including additional tax, late payment interest and penalties.

However, there is an important distinction between calculating the rental profit and calculating the final amount payable to HMRC.

You normally need to calculate the additional Income Tax liability first. The HMRC disclosure calculator can then help you work out the interest and penalties.

Does HMRC provide a Let Property Campaign calculator?

Yes. HMRC provides an official calculator to help individuals calculate interest and penalties when making voluntary disclosures.

The calculator can cover liabilities going back up to 20 years.

You can access the relevant HMRC guidance here:

• HMRC – Let Property Campaign
• HMRC – Penalties and interest calculator

The calculator is designed to help with interest and penalties, not to calculate your rental profits or the underlying Income Tax liability.

You must establish the additional tax due for each year before using it.

What information do you need?

Before using the calculator, you should have the following information available:

1. The tax years covered by your disclosure.
2. Your original taxable income for each year.
3. Your additional rental profits.
4. The additional Income Tax liability for each year.
5. The date the original tax was due.
6. The reason why the income was not declared.
7. Whether the disclosure is prompted or unprompted.

You should also understand the difference between a failure to notify HMRC and an inaccuracy in a previously submitted tax return.

These can result in different penalty calculations.

Example: Calculating undeclared rental income

Let’s consider a landlord who has employment income and has also been renting out a residential property.

The landlord has not declared the rental income for one tax year.

The figures are:

Description	Amount
Employment income	£30,000
Rental income	£15,000
Allowable rental expenses	£3,000
Rental profit	£12,000
Additional Income Tax at 20%	£2,400

For simplicity, assume the entire additional rental profit is taxed at 20%, with no other adjustments.

The landlord’s additional Income Tax liability would be £2,400.

However, this is not the final amount payable.

The landlord must also consider:

• Late payment interest.
• The applicable penalty.
• Any other relevant tax adjustments.

The final disclosure could therefore be considerably higher than the original £2,400 tax liability.

How are penalties calculated?

HMRC does not apply one fixed penalty percentage to every Let Property Campaign disclosure.

The penalty depends on the behaviour that caused the unpaid tax and the quality of the disclosure.

For certain failures to notify, the statutory penalty ranges can be substantial.

For UK income, the maximum penalty can reach 100% of the unpaid tax. Offshore liabilities can carry higher maximum penalties.

However, voluntary disclosure can significantly reduce the penalty.

The following table gives a simplified explanation of the different circumstances.

Behaviour	General penalty position
Reasonable care taken	Normally no penalty
Careless failure	Penalty may be reduced through disclosure
Deliberate failure	Higher penalty range
Deliberate and concealed failure	Potentially the highest penalty range

For example, imagine two landlords who each failed to declare £5,000 of rental profit.

The first landlord misunderstood the reporting requirements and took reasonable steps to comply with tax rules.

The second landlord deliberately concealed the rental income.

Even though the unpaid tax might be identical, HMRC could calculate substantially different penalties because their behaviour was different.

Unprompted and prompted disclosures

The distinction between an unprompted and prompted disclosure is particularly important.

An unprompted disclosure generally means you come forward before HMRC has approached you about the particular failure or discovered it.

A prompted disclosure generally means HMRC has already made contact or taken action that has prompted you to disclose the unpaid tax.

The distinction can affect the minimum penalty percentage available.

For example, someone who discovers that they have forgotten to declare rental income and contacts HMRC before any investigation begins may qualify for a more favourable penalty reduction than someone who only discloses after HMRC starts asking questions.

HMRC also considers how much help you provide when making the disclosure.

This is sometimes described through three elements:

• Telling: Explaining what happened and providing the relevant information.
• Helping: Assisting HMRC with its enquiries and calculations.
• Giving access: Providing relevant records and supporting documents.

A complete and accurate disclosure, made promptly, can help reduce the penalties.

You should not automatically select the lowest penalty percentage simply because you are making a voluntary disclosure. The circumstances need to support it.

Can you use the calculator for several tax years?

Yes. HMRC’s calculator can be used for multiple-year disclosures.

Where you are disclosing several years, HMRC instructs you to include all the relevant years in a single calculation rather than treating each year as a completely separate disclosure.

This is important because the calculator needs to take account of the relevant liabilities and disclosure circumstances.

However, you should still calculate the additional Income Tax separately for each tax year before entering the information.

If you have rental income, employment income, savings interest, pension income or other sources of income, you may need to make additional adjustments.

The calculator is not suitable for every tax situation, so professional advice may be appropriate where the calculations are complicated.

Let Property Campaign Accountant

Using a Let Property Campaign accountant can make the disclosure process considerably easier, particularly if you have several years of undeclared rental income.

Although landlords can make their own disclosures, the calculations can become complicated when several tax years are involved.

An accountant can help you reconstruct your rental accounts, calculate additional tax, establish the correct disclosure period and prepare the figures required by HMRC.

What can an accountant do for you?

A suitably experienced accountant or tax adviser can help with the entire disclosure process.

This normally includes:

1. Reviewing your circumstances

The first step is understanding why the rental income was not declared.

An accountant should establish whether you failed to register for Self Assessment, submitted incorrect tax returns or misunderstood the reporting requirements.

This helps determine which disclosure route and penalty rules may apply.

2. Establishing the correct tax years

An accountant can review your rental history and establish which years need to be included.

This is particularly important where HMRC has already issued tax returns for certain years or where the disclosure covers a lengthy period.

3. Reconstructing rental accounts

If you have incomplete records, an accountant can help reconstruct rental income and expenditure using available documents.

This may involve reviewing bank statements, mortgage statements, letting agent records and historical receipts.

4. Calculating additional Income Tax

An accountant can calculate the correct rental profit and additional Income Tax for each relevant year.

They should consider historical tax rates, personal allowances, other income, property losses and residential finance cost restrictions.

5. Calculating interest and penalties

The accountant can help establish the appropriate penalty behaviour category and calculate the interest and penalties using HMRC’s guidance and calculator.

This is one of the more complicated parts of the process because an incorrect penalty calculation could result in HMRC rejecting the disclosure.

6. Preparing and submitting the disclosure

An accountant can notify HMRC on your behalf, prepare the disclosure and help ensure the required information is submitted within the 90-day deadline.

They can also communicate with HMRC where further clarification is needed.

How much does a Let Property Campaign accountant cost?

There is no fixed HMRC fee for using an accountant to prepare a Let Property Campaign disclosure.

Professional fees depend on the complexity of the case.

For example, a landlord with one property and two years of relatively straightforward rental records may need considerably less work than someone with several properties and 15 years of undeclared rental income.

Factors that can influence the cost include:

• Number of tax years involved.
• Number of rental properties.
• Availability of historical records.
• Complexity of allowable expenses.
• Whether previous Self Assessment returns need correcting.
• Complexity of penalty calculations.
• Whether HMRC has already contacted the landlord.

When asking for a quotation, explain how many properties you own, how many years are involved and whether you have your rental records.

This will help the accountant provide a more realistic estimate.

What should you look for when choosing an accountant?

Not every accountant regularly deals with voluntary disclosures.

Ideally, you should find someone who understands HMRC’s Let Property Campaign and has experience preparing historical rental income calculations.

Look for an accountant who:

• Understands HMRC disclosure procedures.
• Has experience with historical rental income calculations.
• Understands the difference between careless and deliberate behaviour.
• Can calculate historical tax liabilities accurately.
• Understands HMRC interest and penalty calculations.
• Can explain the process and fees clearly.

You should also make sure the accountant is appropriately qualified and authorised to act for you where necessary.

An accountant should never promise that HMRC will accept a particular penalty percentage or guarantee that you will avoid an investigation.

The purpose is to prepare a correct and complete disclosure based on your actual circumstances.

Can you make a Let Property Campaign disclosure yourself?

Yes. You do not have to appoint an accountant.

If you have one rental property, good records and a straightforward tax position, you may be able to prepare the calculations yourself.

However, if you have several years of undeclared income, multiple sources of income or uncertainty about penalties, professional assistance can be worthwhile.

An incorrect disclosure could create further problems, particularly if you underestimate the tax or fail to include income that should have been disclosed.

You can also read our guide explaining whether you can complete a Self Assessment tax return yourself.

What happens after submitting the disclosure?

Once HMRC receives your disclosure, it will review the information provided.

HMRC may contact you or your accountant if it needs clarification or supporting evidence.

If HMRC accepts your disclosure, it will send an acceptance letter.

You should keep a copy of the disclosure, calculations, payment confirmation and any correspondence with HMRC.

If you later discover that you have missed some rental income or made a mistake, you should contact HMRC promptly to correct the disclosure.

A disclosure should be treated as a complete account of the unpaid tax rather than an opportunity to report only some of the rental income.

What happens if you cannot afford to pay the outstanding tax?

Not every landlord will have enough money available to pay several years of outstanding tax, interest and penalties in one payment.

HMRC may consider a Time to Pay arrangement where you cannot afford to settle the full amount immediately.

You should contact the Let Property Campaign helpline before submitting your disclosure if you cannot pay the full amount.

HMRC will want to understand your financial position, including your income, expenditure, assets and existing debts.

It will then consider whether an instalment arrangement is appropriate.

Do not assume that you automatically qualify for a payment plan. HMRC will assess your circumstances.

Conclusion

The Let Property Campaign provides individual landlords with an opportunity to correct previously undeclared residential rental income and bring their tax affairs up to date.

Although the process may initially seem complicated, it becomes easier when you approach it systematically.

Start by establishing which tax years are relevant, gathering your rental records and calculating the additional rental profits. You can then work out the Income Tax, interest and penalties before submitting your disclosure to HMRC.

Remember that coming forward voluntarily can result in lower penalties than waiting for HMRC to discover the problem.

If you have several years of undeclared rental income or are unsure how to calculate your tax and penalties, consider speaking to an accountant experienced in HMRC voluntary disclosures.

Need help with undeclared rental income?

Better Account provides accounting and tax support to individuals and landlords. We can help you understand your rental income, review your tax position and prepare the calculations needed to bring your tax affairs up to date.

Visit Better Account to find out more about our accounting services.

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