HMRC Owes You Tax from Previous Years? Here’s How to Claim Your Refund

You could be owed hundreds or even thousands of pounds in overpaid Income Tax from previous years. But changes to HMRC’s repayment procedures mean you may need to take action to receive the money.

Many employees and pensioners assume that if they’ve overpaid Income Tax, HMRC will automatically return the money.

Unfortunately, that’s not always the case.

HMRC’s tax reconciliation process can identify overpayments covering several tax years.

Where this happens, the way refunds are requested and paid is important.

HMRC has been moving towards digital repayment services, including changes affecting multi-year tax refunds.

Understanding the process can help you recover money you’re entitled to without unnecessary delays.

Why might you have overpaid tax in previous years?

Income Tax overpayments can arise for several reasons.

You may have:

• Changed jobs and been placed on an incorrect tax code.
• Worked for only part of a tax year.
• Had more than one employer.
• Started or stopped receiving a pension.
• Been taxed incorrectly on multiple income sources.
• Failed to claim an available employment expense relief.
• Had an incorrect tax code applied for several years.

In some cases, the same issue can affect consecutive tax years.

For example, an incorrect tax code might result in additional tax being deducted year after year without the taxpayer realising.

Can you claim refunds for more than one tax year?

Yes.

HMRC can issue tax calculations relating to several previous tax years where its records show that Income Tax has been overpaid.

However, there are time limits for making repayment claims.

In many circumstances, the normal time limit is four years after the end of the tax year concerned.

For example, the usual deadline for making a qualifying claim relating to the 2022/23 tax year is 5 April 2027.

Different rules can apply depending on the type of claim, so it is important to identify the correct process.

Leaving a potential refund unclaimed for too long could mean losing the opportunity to recover it.

How is HMRC changing the repayment process?

HMRC has been increasing the use of digital services for Income Tax repayments.

Its August 2026 Employer Bulletin explained changes affecting many employees who claim refunds covering more than one tax year.

Rather than automatically issuing a cheque in every case, HMRC may require taxpayers to request their repayments.

Once HMRC has processed the relevant tax calculations, it may issue a P800 letter explaining how to claim the money.

The precise process depends on the instructions in your letter.

Some taxpayers will be invited to request payment online, while others may still receive an automatic cheque.

How do you claim your money?

If your P800 says that you can request a refund online, the process is generally straightforward.

Step 1: Check the P800 calculation

Make sure HMRC has included the correct income and tax figures for each year.

Step 2: Check the repayment instructions

Your P800 will explain whether you need to request payment or whether HMRC will issue a cheque automatically.

Step 3: Visit the official HMRC service

Use the HMRC Personal Tax Account, HMRC app or the relevant repayment service on GOV.UK.

Step 4: Provide the required information

You may need your National Insurance number and the reference shown on the P800.

Step 5: Request your repayment

Where eligible, you can ask for the refund to be transferred to a UK bank account.

HMRC normally processes eligible online repayment requests within five working days.

You can also request a cheque where the service offers that option, although postal repayments generally take longer.

Example: Three years of overpaid tax

Imagine you’ve been employed continuously but had an incorrect PAYE tax code applied over several years.

After reviewing your records, HMRC identifies the following overpayments:

Tax year	Tax overpaid
2023/24	£420
2024/25	£570
2025/26	£360
Total refund	£1,350

Instead of recovering a small amount from one year, you could be entitled to £1,350 covering all three years.

The repayment process will depend on the individual calculations and the instructions HMRC issues.

This illustrates why checking previous tax years can be worthwhile.

What if you don’t use online services?

HMRC recognises that not everyone is comfortable using digital services.

Taxpayers who cannot use online services, or who prefer a cheque, can normally contact HMRC to discuss alternative repayment arrangements.

However, postal repayments may take longer.

You should not need to pay a third-party refund company simply to access money that HMRC already owes you.

Are tax refund companies worth using?

Some businesses offer to obtain tax refunds in exchange for a percentage of the repayment.

While legitimate refund services exist, taxpayers should understand how much they will be charged and what work is actually being undertaken.

For straightforward repayments identified by HMRC, you can often claim directly without paying a fee.

Where your tax position is more complicated, professional advice may be valuable, particularly if several years of employment, pensions or allowances need reviewing.

What if HMRC hasn’t identified your refund?

Not every overpayment is automatically picked up through the P800 process.

For example, you may be entitled to tax relief for qualifying employment expenses that HMRC does not already know about.

You may need to make a specific claim, amend a tax return or provide additional information.

The correct route depends on the nature of the overpayment.

Don’t let an old tax refund expire

Tax repayment deadlines can be easy to overlook.

If you think you’ve paid too much tax in previous years, it is sensible to review the position before the relevant time limit expires.

Useful documents include:

• P60s and P45s.
• Payslips and pension statements.
• Previous tax calculations.
• Employment expense records.
• HMRC correspondence.

Even relatively modest annual overpayments can add up over several years.

How williams lester accountants can help

At williams lester accountants, we help individuals establish whether they’ve paid the correct amount of Income Tax.

We can review previous tax years, identify potential overpayments, assess the appropriate claim procedures and assist with more complicated HMRC enquiries.

We can also help where overpayments involve multiple employments, pensions, Self Assessment or other income sources.

Think HMRC might owe you money?

Don’t leave a potential refund unclaimed.

Speak to williams lester accountants about reviewing your tax position and identifying any repayments that may be available.

This article reflects HMRC’s P800 repayment guidance and changes announced during 2026. Repayment methods and time limits depend on the type of overpayment and individual circumstances.