If you have received a P800 letter from HMRC telling you that you overpaid tax, there is something important you need to know: HMRC no longer sends refund cheques automatically.
Since 31 May 2024, the old system where a cheque arrived in the post after 21 days has ended. Now, if you do not actively claim your refund, you will not receive it. Your money will simply sit on your tax record, unclaimed.
This is a significant change that many taxpayers are unaware of. Millions of pounds in tax refunds go unclaimed every year, and without action, yours could be one of them.
This guide explains what has changed, how to claim your P800 refund, and what happens if you do nothing.
Key Takeaways
- From 31 May 2024, HMRC stopped sending automatic cheques for P800 tax refunds
- You must now claim your refund yourself through the online service, HMRC app, or Personal Tax Account
- If you do not claim, your refund will remain unclaimed on your tax record
- Online bank transfers arrive within five working days; cheques (if requested) take up to six weeks
- You can still claim refunds for the previous four tax years, but time limits apply
- Always check your P800 figures are correct before claiming, as HMRC calculations can contain errors
What Changed in May 2024?
Before 31 May 2024, the P800 system worked like this: HMRC would send you a letter showing your tax calculation.
If you were owed a refund and did not claim it online within 21 days, HMRC would automatically post you a cheque.
That automatic cheque no longer exists.
HMRC made this change to encourage online claims and reduce fraud. Under the new system, if you receive a P800 showing a refund is due, you must take action. No action means no refund.
P800 letters are often sent out between June and November each year. If you received one and assumed a cheque would follow, it might not.
How to Check If You Have an Unclaimed P800 Refund
You can check whether you have an unclaimed tax refund in several ways.
Personal Tax Account: Log in to your HMRC Personal Tax Account at gov.uk/personal-tax-account. Any unclaimed refunds will appear on your tax record. You can also see previous P800 calculations here.
HMRC App: The free HMRC app shows your tax position and any refunds due. Download it from the App Store or Google Play.
P800 Letter: If you received a P800 letter in the post within the last few years but never acted on it, the refund may still be available. You will need the reference number from the letter to claim.
Contact HMRC: If you have lost your P800 letter or cannot access online services, call HMRC on 0300 200 3300. Have your National Insurance number ready.
How to Claim Your P800 Refund
There are three ways to claim your tax refund from HMRC. The fastest is online.
Option 1: Online Bank Transfer (Recommended for most)
This is the quickest method. Your refund typically arrives within five working days.
Step 1: Go to gov.uk/tax-overpayments-and-underpayments
Step 2: Enter the reference number from your P800 letter and your National Insurance number
Step 3: Verify your identity (you may need your passport or payslip details)
Step 4: Enter your bank details for the transfer
Step 5: Submit your claim
You will receive confirmation on screen and the money should reach your account within five working days.
Option 2: Request a Cheque Online
If you prefer a cheque, you can request one through the same online process. However, cheques now take up to six weeks (42 days) to arrive, compared to five days for a bank transfer.
Option 3: Claim by Phone
If you cannot use online services, call HMRC on 0300 200 3300 and ask them to send a cheque. You will need your National Insurance number and details from your P800 letter if you have it.
HMRC’s phone lines can be busy, so expect a wait. Opening hours are Monday to Friday, 8am to 6pm.
What If You Never Received a P800 Letter?
Not everyone who overpays tax receives a P800. HMRC’s system only generates a P800 when their records show you have overpaid.
If the underlying data is wrong, the overpayment may never be detected.
Common reasons for overpaying tax that might not trigger a P800 include:
- Unclaimed work expenses: If you paid for uniforms, tools, or mileage out of your own pocket and never claimed tax relief, HMRC does not know about it
- Wrong tax code applied: If your employer used an incorrect tax code but HMRC’s records do not flag an error, no P800 is generated
- Multiple jobs with split allowances: If your personal allowance was not correctly allocated between employers
- Starting mid-year: If you started work part-way through the tax year and were taxed as if you would earn a full year’s salary
In these cases, you need to make a separate claim rather than waiting for a P800. Use form P87 for work expenses under £2,500, or Self Assessment for larger claims.
What Happens If You Do Not Claim?
If you do not claim your P800 refund, the money remains on your HMRC record. It does not disappear immediately, but there is a time limit.
The four-year rule: You can claim a tax refund for the current tax year plus the previous four tax years. After that, the entitlement expires.
For example, as of the 2025/26 tax year (which runs from 6 April 2025 to 5 April 2026), you can still claim refunds back to 2021/22.
But the deadline to claim 2021/22 refunds is 5 April 2026. After that date, any unclaimed refund for that year is gone.
If you have old P800 letters you never acted on, check whether the tax years involved are still within the four-year window.
Always Check Your P800 Is Correct
Before claiming any refund, check that the figures on your P800 are accurate. HMRC’s calculations are based on the information they hold, which may be incomplete or wrong.
Cross-check against:
- Your P60 (annual summary from your employer)
- Your P45 (if you changed jobs during the year)
- Your payslips (to verify total pay and tax deducted)
- Your P11D (if you received taxable benefits like a company car)
Common P800 errors include:
- Missing income: A second job or pension not included in the calculation
- Wrong personal allowance: Particularly if you are a Scottish taxpayer or receive Marriage Allowance
- Benefits not accounted for: Company car, private medical insurance, or other taxable benefits
- Expenses not included: Work expenses you claimed should reduce your tax bill
If the P800 figure looks lower than expected, it may be worth investigating further before accepting the refund shown.
If the P800 figure looks higher than expected, be cautious. Accepting a refund you are not entitled to could lead to HMRC clawing it back later, possibly with interest.
Could You Be Owed More Than the P800 Shows?
A P800 only reflects what HMRC knows about. If you are entitled to tax relief that HMRC is unaware of, your actual refund could be higher.
Additional reliefs to consider:
- Uniform and laundry allowance: If you wear a uniform for work and wash it yourself, you can claim a flat-rate allowance (currently £60 per year for most workers, more for certain professions)
- Professional subscriptions: Membership fees for HMRC-approved professional bodies are tax-deductible
- Mileage allowance: If you use your own vehicle for work journeys (not commuting) and are not fully reimbursed by your employer, you can claim up to 45p per mile
If any of these apply, consider making a separate claim using form P87 or through your Personal Tax Account. This is in addition to any automatic P800 refund.
Beware of P800 Scams
HMRC will never email, text, or call you out of the blue to tell you that you are owed a tax refund.
If you receive a message asking for your bank details or personal information, it is almost certainly a scam.
Genuine P800 letters:
- Arrive by post only
- Include your correct name and National Insurance number
- Direct you to gov.uk/tax-overpayments-and-underpayments to claim
- Never ask you to click a link in an email or text
Scam warning signs:
- Emails or texts claiming to be from HMRC
- Requests for immediate action or threats of penalties
- Links to websites that are not gov.uk
- Requests for bank details by email, text, or phone
If you are unsure whether a communication is genuine, do not click any links or provide any information. Go directly to gov.uk or call HMRC on 0300 200 3300 to verify.
What If You Underpaid Tax?
A P800 can also show that you owe HMRC money. This happens when you did not pay enough tax during the year.
Common reasons for underpayment include:
- Two jobs where both employers gave you the full personal allowance
- Taxable benefits (company car, medical insurance) not collected through payroll
- State Pension income not correctly accounted for in your tax code
- Emergency tax code that was never corrected
If you owe less than £3,000: HMRC will normally collect the underpayment by adjusting your tax code for the following year. You pay a little more tax each month until the debt is cleared.
If you owe £3,000 or more: HMRC will usually ask you to pay the amount directly rather than through your tax code. You should receive a Simple Assessment (form PA302) with payment details.
If you believe the underpayment calculation is wrong, contact HMRC before the deadline shown on the letter.
How Much Could You Be Owed?
The average P800 refund varies, but amounts of £200 to £500 are common. Some taxpayers receive over £1,000, particularly if errors spanned multiple years or they changed jobs several times.
Example 1: Job change mid-year
Sarah earned £25,000 in her first job (April to September) and was taxed on the assumption she would earn £50,000 for the full year.
She then started a new job in October earning £30,000 pro-rata. Because her personal allowance was not correctly applied between employers, she overpaid £420 in tax. Her P800 showed this and she claimed the refund online.
Example 2: Emergency tax code
James started a new job without a P45. His employer put him on an emergency tax code for three months before HMRC issued the correct code. During those three months, he overpaid £380. HMRC sent a P800 the following summer.
Example 3: Unclaimed expenses plus P800
Emma received a P800 showing a £150 refund due to a tax code error. However, she also spent £300 on professional subscriptions and £200 on work uniform maintenance that she had never claimed. By submitting a P87 for these expenses, she received an additional £100 tax relief on top of her P800 refund.
P800 Tax Refund: Key Takeaways
- From 31 May 2024, HMRC stopped sending automatic cheques for P800 tax refunds
- You must now claim your refund yourself through the online service, HMRC app, or Personal Tax Account
- If you do not claim, your refund will remain unclaimed on your tax record
- Online bank transfers arrive within five working days; cheques (if requested) take up to six weeks
- You can still claim refunds for the previous four tax years, but time limits apply
- Always check your P800 figures are correct before claiming, as HMRC calculations can contain errors
P800 Refund Frequently Asked Questions
I received a P800 last year but never claimed. Is it too late?
Probably not. You can claim refunds for the current tax year plus the previous four years. Check your Personal Tax Account to see if the refund is still available. Act quickly if the tax year involved is approaching the four-year deadline.
Can I claim a P800 refund on behalf of someone else?
You can help someone else make a claim, but the refund will be paid to them, not you. If the person has died, you may need to contact HMRC about claiming on behalf of an estate.
Why did I receive a P800 showing I owe money?
A P800 can show underpayment as well as overpayment. Common causes include incorrect tax codes, multiple employments, or taxable benefits. Read the letter carefully and contact HMRC if you believe it is wrong.
What if I disagree with my P800 calculation?
Check the figures against your P60, payslips, and P11D. If you believe HMRC has made an error, contact them on 0300 200 3300 with evidence. Do not ignore an underpayment demand if you believe it is incorrect—respond within the deadline given.
How long does it take to receive my refund?
Online bank transfers arrive within five working days. Cheques take up to six weeks (42 days). If you have been waiting longer, contact HMRC.
Will claiming a P800 refund affect my tax code?
Claiming a P800 refund should not affect your current tax code, as the P800 relates to a previous tax year. However, if the overpayment was caused by an ongoing error (such as a wrong tax code), HMRC may correct your code going forward.
