9-minute read
To write to HMRC effectively: include your full name, address, date of birth, National Insurance number and (if applicable) UTR; reference the tax year clearly (e.g. "2024/25 — tax year ending 5 April 2025"); state the action you want HMRC to take; send by signed-for or recorded delivery so you have proof of postage. Most non-urgent queries get a written response in 15-40 working days. Use the correct postal address for your query type (different addresses for PAYE, Self Assessment, NI, complaints).
Why writing beats phoning for some queries
HMRC phone lines are overwhelmed. Average wait times exceeded 20 minutes for much of 2024-25, with peaks of an hour in January. A clear, well-formatted letter:
- Creates a written record HMRC must process
- Is handled by a different team to the phone agents (often more thoroughly)
- Gives you a paper trail if HMRC later denies or forgets the query
- Forces HMRC to provide a written response — useful for complaints escalation
- Is the only acceptable route for some queries (e.g. formal review requests)
When to write vs. phone vs. onlinePhone: simple factual updates (change of address, simple tax code query). Online: refund claims via Personal Tax Account, tax code updates, Self Assessment filing. Post: formal appeals, complex disputes, R40 paper claims, anything where you need a paper trail. App: tax code check, payment, simple notification.
HMRC postal addresses by query type
| Query type | Address |
|---|---|
| PAYE / tax code / employed | Pay As You Earn and Self Assessment HM Revenue and Customs BX9 1AS United Kingdom |
| Self Assessment | Self Assessment HM Revenue and Customs BX9 1AS United Kingdom |
| National Insurance | National Insurance Contributions and Employers Office HM Revenue and Customs BX9 1AN United Kingdom |
| Tax credits / Child Benefit | Tax Credit Office HM Revenue and Customs BX9 1ER United Kingdom |
| VAT | HM Revenue and Customs VAT Written Enquiries Team 123 St Vincent Street Glasgow City G2 5EA |
| Complaints | HMRC Complaints HM Revenue and Customs BX9 1AB United Kingdom |
BX9 is not a real postcode. It's an HMRC bulk-mail centre. Royal Mail handles it but no automated lookup tool will validate it. Print exactly as shown above — don't try to "fix" it.
Template 1 — Request a tax code change
Use this when your tax code is wrong and you want HMRC to update it before your next pay date. Send to PAYE address (BX9 1AS).
[Your full address]
[Postcode]
[Date]
PAYE and Self Assessment
HM Revenue and Customs
BX9 1AS
Dear HMRC,
Re: Request to update tax code — [Tax year, e.g. 2026/27]
National Insurance number: [QQ 12 34 56 A]
Date of birth: [DD/MM/YYYY]
Employer PAYE reference: [123/AB456]
I am writing to ask you to update my tax code from [current code, e.g. 1100L] to [requested code, e.g. 1257L] for the following reason:
[Brief explanation, e.g. "I have moved from a second employment to a single employment as of 1 April 2026" or "I am no longer receiving company car benefit from my employer".]
Please could you issue an updated tax code to my employer at the earliest opportunity so my next payslip reflects the correct deduction.
I enclose a copy of [supporting document, e.g. payslip / P45 / employer confirmation letter].
Thank you for your help.
Yours faithfully,
[Signature]
[Full name printed]
[Daytime telephone number]
[Email if you have one]
Template 2 — Request a refund (not via Self Assessment)
Use this if you've overpaid PAYE during the year and want a refund mid-year, OR if your overpayment isn't picked up by automatic P800 reconciliation. Send to PAYE address.
[Your full address]
[Postcode]
[Date]
PAYE and Self Assessment
HM Revenue and Customs
BX9 1AS
Dear HMRC,
Re: Claim for tax refund — [Tax year, e.g. 2024/25]
National Insurance number: [QQ 12 34 56 A]
I am writing to claim a refund of overpaid tax for the tax year ending 5 April [YYYY].
The overpayment arose because [brief explanation, e.g.:]
"I left my employer on [date] and did not work again that tax year. My P45 shows total pay of £[X] and total tax paid of £[Y]. As my income was below the Personal Allowance for the year, no tax should have been due, and I am owed £[Y] in refund."
OR
"I was on an emergency tax code (W1/M1) for [number] months and have since received my P60 showing my correct annual income of £[X]. The PAYE deducted was £[Y]. Based on the standard tax code 1257L for that year, the correct tax due was £[Z]. I am therefore owed £[Y - Z] in refund."
I enclose copies of:
• My P60 for the year ended 5 April [YYYY]
• [Other supporting documents]
Please pay any refund due to my bank account:
Account name: [Name on account]
Sort code: [XX-XX-XX]
Account number: [XXXXXXXX]
Yours faithfully,
[Signature]
[Full name printed]
[Daytime telephone number]
HMRC typically does not pay refunds without a bank account.If you don't include account details, HMRC issues a cheque, which adds 3-4 weeks. Including bank details speeds payment significantly.
Template 3 — Penalty appeal
Use this within 30 days of a penalty notice if you believe the penalty should not apply or should be reduced. Send to the address shown on the penalty letter (usually BX9 1AS for Self Assessment penalties).
[Your full address]
[Postcode]
[Date]
[Address shown on penalty letter]
Dear HMRC,
Re: Appeal against penalty — Reference [Penalty reference, e.g. SA12345]
National Insurance number: [QQ 12 34 56 A]
UTR: [10-digit UTR]
Tax year: [e.g. 2023/24]
I am writing within 30 days of the penalty notice dated [date] to formally appeal the penalty of £[amount] for [reason given by HMRC].
I appeal on the following grounds:
[Choose appropriate grounds — examples below:]
REASONABLE EXCUSE: I was unable to meet the deadline because [serious illness, bereavement, fire/flood, postal disruption, COVID isolation, computer/software failure that I could not reasonably have anticipated]. I attach supporting evidence: [doctor's note, death certificate, postal receipts, etc.]
OR
INCORRECT INFORMATION: HMRC's records appear to show [X] which is incorrect. The correct position is [Y]. I attach [evidence]. The penalty was therefore issued in error.
OR
DOUBLE-TAXED: HMRC has issued penalties for both the late return (£100) and the late payment when the underlying tax has already been paid via [PAYE / Direct Debit on date X]. The late-payment penalty should be cancelled.
I request that HMRC:
• Cancel the penalty in full, OR
• Reduce the penalty in line with HMRC's published reasonable-excuse guidance
• Confirm the outcome in writing
If HMRC declines the appeal, I request a formal review (the next stage of the appeal process) and reserve the right to appeal to the First-tier Tribunal (Tax Chamber).
Yours faithfully,
[Signature]
[Full name printed]
[Daytime telephone number]
Template 4 — PAYE underpayment dispute
Use this if HMRC has issued a tax code change because of a claimed underpayment from a previous year, and you don't believe the underpayment is correct. Send to PAYE address.
[Your full address]
[Postcode]
[Date]
PAYE and Self Assessment
HM Revenue and Customs
BX9 1AS
Dear HMRC,
Re: Disputed underpayment for tax year [YYYY/YY]
National Insurance number: [QQ 12 34 56 A]
Employer PAYE reference: [123/AB456]
Current tax code: [code]
I have received a P800 / tax code notice dated [date] showing an underpayment of £[X] for the tax year ended 5 April [YYYY]. I do not agree with this calculation for the following reasons:
[List the specific points, with evidence:]
1. My P60 for that year shows total pay of £[X] and tax paid of £[Y].
2. My only employer that year was [Employer name].
3. HMRC's calculation appears to assume [different income / different tax paid].
4. [Other discrepancies with evidence attached]
I request that HMRC:
• Review the underpayment calculation in light of the enclosed P60 and bank statements
• Suspend the tax code adjustment until the dispute is resolved
• Confirm in writing what records HMRC holds for the disputed year
• If the underpayment is correct, I request the right to spread the recovery over a longer period than the proposed [12 months]
I enclose copies of:
• P60 for [year]
• Payslips for [relevant months]
• [Other evidence]
Please confirm receipt of this letter and acknowledge that the underpayment is disputed pending review.
Yours faithfully,
[Signature]
[Full name printed]
[Daytime telephone number]
What to include — checklist before posting
Mandatory in every letterFull name. Full residential address with postcode. Date of letter. National Insurance number. Date of birth. Subject line specifying the tax year. Signature (handwritten ink). Daytime phone number.
Add if relevant to queryUTR (10-digit Self Assessment number). Employer's PAYE reference (from payslip). Pension scheme reference. Bank details for refund. Reference number from any HMRC letter you're responding to.
Always enclose copies, not originalsP60, P45, payslips, bank statements, letters — always send photocopies. HMRC routinely loses post and does not return original documents. Keep all originals at home.
Send signed-for delivery£2-£3 from a Post Office gives you a tracking number and proof of delivery. Indispensable if HMRC later claims it never received the letter. Keep the receipt for at least 12 months.
Common mistakes that delay HMRC responses
Mistake 1: Missing the NI number. Without your NI number, HMRC cannot match the letter to your record. Many letters are simply returned or filed unanswered.
Mistake 2: Vague subject lines. "Re: Refund" is too vague. Use "Re: Refund claim for tax year ended 5 April 2025 — NI number QQ123456A".
Mistake 3: Sending originals. If HMRC loses your P60 original, you cannot get a duplicate from your employer easily. Send copies.
Mistake 4: No phone number. If a quick clarification is needed, HMRC often phones rather than writing back. Without a number, HMRC may delay or close the query unresolved.
Mistake 5: Multiple unrelated queries in one letter. Each query goes to a different team. Send separate letters for separate issues — they're processed faster.
HMRC response times by query type
| Query type | Typical response (working days) | Worst case |
|---|---|---|
| Tax code change request (simple) | 10-20 | 40+ |
| Refund claim with full documentation | 20-30 | 60+ |
| Penalty appeal (clear reasonable excuse) | 15-30 | 45+ |
| Underpayment dispute (complex) | 40-60 | 120+ |
| Complaints (Tier 1) | 15-25 | 60+ |
| Complaints (Tier 2 / Adjudicator) | 60-120 | 180+ |
If you haven't had a written response within 8 weeks, write a chaser letter referencing the original letter date and ask for a status update. This often unblocks slow cases.
Decode an HMRC letter you've received
Got an HMRC letter you don't understand? The HMRC Letter Decoder explains the most common letter codes (P800, P2, SA250, K-code notice, penalty notice) and what to do next.
Open the HMRC Letter Decoder →Sources and references
HMRC contact addresses from gov.uk HMRC contact pages. Penalty appeal grounds from gov.uk/tax-appeals. Self Assessment appeal guidance from gov.uk Self Assessment penalties. Response times from HMRC Service Performance reports.
UK Tax Drag is not authorised by the Financial Conduct Authority and does not provide regulated financial or tax advice — see the content disclaimer for the full position. The methodology page documents how every guide is built and reviewed.
Other HMRC how-to guides
- How to write to HMRC — template letters
- How to check your tax code online
- How to register for Self Assessment
- Self Assessment walkthrough 2026/27
- How to claim higher-rate pension relief
- How to claim Marriage Allowance retrospectively
- How to claim work-from-home tax relief
- How to dispute a tax bill
- HMRC phone wait times + contact channels
- What to do if you can't pay your tax bill
- HMRC Response Centre (hub)
Editorial accountability
Open Trust Centre →
How UK Tax Drag holds itself to account
Every page is reviewed against the editorial standards, written from primary sources, sourced openly, and corrected publicly. No affiliate revenue. No sponsored content. No paid placements.