--- title: "HMRC Simple Assessment Letter: Can You Challenge It?" url: https://taxdisputes.co.uk/2026/11/hmrc-simple-assessment-challenge/ date: 2026-11-03 modified: 2026-11-03 lang: en author: "Tax Dispute Solicitors" description: "Got an HMRC simple assessment letter and think the tax is wrong? Find out the 60 day deadline to query it, when you can appeal, whether you must pay while HMRC looks at it and what to do if the date has passed." categories: - "Appeals" - "Discovery assessment" - "Dispute Resolution" - "First Tier Tax Tribunal" - "HMRC" - "HMRC Assessments" - "HMRC Penalty" - "Income tax" - "Tax Issue" - "Tax Law" - "Tax Management Act 1970" - "taxpayer" - "Time to Pay" - "Tribunal Proceedings" - "TTP Arrangements" tags: - "appeal simple assessment" - "challenge HMRC simple assessment" - "HMRC 60 day deadline" - "HMRC simple assessment" - "HMRC Tax Appeal" - "HMRC tax bill wrong" - "postpone simple assessment" - "query simple assessment" - "section 28H Taxes Management Act 1970" - "section 31 Taxes Management Act 1970" - "section 31A Taxes Management Act 1970" - "section 31AA Taxes Management Act 1970" - "section 59BA Taxes Management Act 1970" - "simple assessment letter" - "simple assessment payment deadline" image: https://taxdisputes.co.uk/wp-content/uploads/2026/11/Tax-Deadline-Desk-Arrangement-1-1024x437.png word_count: 1945 --- # HMRC Simple Assessment Letter: Can You Challenge It? Yes, you can challenge an HMRC simple assessment, but the route is narrow: you must first query the bill with HMRC within 60 days of the date on the letter, and you can appeal only after HMRC gives its final response, within 30 days of that response. Until HMRC tells you otherwise the bill stays payable, so start by checking the figures against your own records. Most people who open one of these letters have filed no tax return, have no accountant and did not expect a bill. HMRC said on 28 July 2026 that it would issue [around 1.8 million simple assessment letters](https://www.gov.uk/government/news/hmrc-urges-customers-not-to-ignore-simple-assessment-letters) for the 2025 to 2026 tax year, with a second batch between October and December 2026 based on bank and building society interest. What surprises people is that a letter which reads like a final demand has a built-in challenge process, and that the process runs on two different deadlines. ## What Is an HMRC Simple Assessment Letter? An HMRC simple assessment is a tax bill that HMRC works out itself and posts to you, so you do not have to complete a Self Assessment tax return first. The power sits in [section 28H of the Taxes Management Act 1970](https://www.legislation.gov.uk/ukpga/1970/9/section/28H), and [GOV.UK states](https://www.gov.uk/simple-assessment) that you must pay the bill if HMRC has sent you the letter. The letter should show how the tax was calculated and give a 14-character payment reference that starts with the letter X. HMRC says the letters go to people who owe tax on income that was not taxed through PAYE or Self Assessment. Its examples include untaxed savings or dividend interest, income from a second job or a pension, and an over-claimed tax-free allowance. If the figures look wrong, or you think you owe nothing, our guide to [HMRC tax dispute lawyers](https://www.lexlaw.co.uk/hmrc-tax-dispute-lawyers/) shows how we approach these disputes. ## How to Check Your HMRC Simple Assessment Calculation Start with the income. Lay each figure on the letter beside your own paperwork, such as payslips and savings interest statements. GOV.UK has a page for the case where [the amounts used in your tax calculation are wrong](https://www.gov.uk/understand-simple-assessment/if-the-amounts-used-in-your-tax-calculation-are-wrong), and it asks you to say which amounts you think are incorrect and what they should be. Then check the date and the reference. The date at the top of the letter matters because the 60-day period for querying the bill runs from it, and that you must contact HMRC within 60 days if you think any information is wrong. Our guide to [challenging HMRC tax assessments](https://taxdisputes.co.uk/2025/10/how-to-challenge-hmrc-tax-assessments-and-protect-your-rights/) covers the wider picture, and our page on [HMRC tax appeals](https://taxdisputes.co.uk/hmrc-tax-appeals/) explains how the formal route works. ### Want legal advice from Tax Solicitors on your case? Our simple enquiry form goes immediately to our tax litigators in Middle Temple, London. Call us on +442071830529 from 9am-6pm. [Check My Case Now ✔](https://taxdisputes.co.uk/legal-case-assessment/) ## Can You Appeal an HMRC Simple Assessment? The 60-Day and 30-Day Rules You cannot appeal a simple assessment straight away. You must query it first. [Section 31AA of the Taxes Management Act 1970](https://www.legislation.gov.uk/ukpga/1970/9/section/31AA) lets you tell HMRC that you believe the assessment "is or may be incorrect", giving your reasons, and you must do so within 60 days of the date of the notice or within "such longer period as HMRC may allow". HMRC must then consider the query and give you a final response. A right of appeal arises only after that final response ([sections 31(1)(d) and 31(3A)](https://www.legislation.gov.uk/ukpga/1970/9/section/31)), and the appeal must be made within 30 days after the date on which you are given notice of the final response ([section 31A(1)(b) and (4A)(a)](https://www.legislation.gov.uk/ukpga/1970/9/section/31A)). HMRC’s final response will confirm the assessment or amend it. It may also withdraw the assessment without replacing it. Much general guidance says you have 30 days to appeal an HMRC assessment. For a simple assessment the 30 days starts later, so the 60-day query is the step to protect first. If HMRC confirms the bill and you still disagree, the appeal can lead to an [internal HMRC review](https://taxdisputes.co.uk/hmrc-internal-review-appeals-solicitors-london/) or a hearing at the [First-tier Tribunal (Tax Chamber)](https://taxdisputes.co.uk/first-tier-tax-tribunal-solicitors-london/). Our [HMRC appeal lawyers](https://taxdisputes.co.uk/hmrc-appeal-lawyers-london/) act in these appeals. ## How to Query an HMRC Simple Assessment in Writing GOV.UK says to call or write to HMRC within 60 days of the date on the bill. Writing is safer, because a letter gives you a dated record of what you said and when. Say which amounts are wrong, what they should be and why, enclose copies of your evidence, and keep proof of posting. HMRC may ask to see the records you used. Quote the payment reference and the date of the letter, and ask in the same letter for the assessment to be postponed while HMRC considers your query. HMRC’s own internal guidance on appeals, [ARTG2040](https://www.gov.uk/hmrc-internal-manuals/appeals-reviews-and-tribunals-guidance/artg2040), describes the same query-then-appeal sequence. ## Do You Have to Pay an HMRC Simple Assessment While You Query It? Usually yes, unless HMRC says otherwise. GOV.UK says you must still pay by the deadline unless HMRC tells you it will delay your payment date. The legal basis for a delay is section 31AA(6) to (8): where HMRC needs time to consider the query, it may postpone the assessment in whole or in part, it must tell you in writing, and while the postponement lasts you are "under no obligation to pay" the postponed amount. Postponement is a power HMRC may use, so ask for it in your query, but treat the bill as payable until you hold HMRC’s written notice. If you agree with part of the figure, paying that part removes any argument over it. If you cannot afford the amount due, GOV.UK explains how to [set up a payment plan](https://www.gov.uk/guidance/find-out-how-to-pay-a-debt-to-hmrc-with-a-time-to-pay-arrangement), and our pages on [Time to Pay arrangements](https://taxdisputes.co.uk/2026/04/hmrc-time-to-pay-arrangements-explained/), [what a Time to Pay arrangement is](https://taxdisputes.co.uk/2026/05/what-is-a-time-to-pay-arrangement/) and [negotiating a repayment plan for unpaid tax](https://lexlaw.co.uk/solicitors-london/hmrc-time-to-pay-arrangement-guide-2026-how-to-negotiate-a-repayment-plan-for-unpaid-tax/) cover the detail. ## HMRC Simple Assessment Payment Deadline for 2025/26 For letters dated before 31 October 2026 about the 2025 to 2026 tax year, GOV.UK gives a payment deadline of 31 January 2027. For a notice given after 31 October, [section 59BA(4) and (5)](https://www.legislation.gov.uk/ukpga/1970/9/section/59BA) makes the tax payable three months after the day on which you were given notice. A letter dated in November 2026 therefore gives you three months from its date. That payment date falls after the 60-day query period ends, so do not treat the payment date as your deadline for challenging the bill. You can pay in full or in instalments, provided the whole bill is cleared by the deadline on your letter. Use the payment reference from the letter, because GOV.UK warns that the wrong reference may delay your payment or send it to a different tax bill. Late payment can add charges to the bill, and our guidance on [HMRC penalties](https://taxdisputes.co.uk/hmrc-penalties/) explains how HMRC approaches them. ## What if the 60 Days Have Already Passed? HMRC began sending letters to working-age customers on 30 June 2026, so some recipients are already past 60 days. The legislation still leaves a way back, because HMRC can accept a query after the 60 days where it allows a longer period. Write as soon as you can, give the date you received the letter and explain why you did not act sooner. HMRC does not have to agree, and if it refuses your options narrow quickly. Our page on [late HMRC tax appeals](https://taxdisputes.co.uk/late-hmrc-tax-appeals/) explains how late challenges are approached, and the sooner you write the easier the delay is to explain. ## Simple Assessment, Self Assessment Return or Discovery Assessment? People searching about these letters often confuse different HMRC documents. A Self Assessment return is a form you file, whereas a simple assessment is a bill HMRC calculates for you. A discovery assessment lets HMRC reopen an earlier year where it believes tax was underpaid, with its own time limits and its own grounds of challenge. Our explainer on [HMRC discovery assessments](https://taxdisputes.co.uk/2026/05/hmrc-discovery-assessments-explained/) and our [guide to challenging discovery assessments](https://lexlaw.co.uk/solicitors-london/ultimate-guide-to-hmrc-discovery-assessments-how-to-challenge-appeal-2026/) cover that different regime. HMRC’s release says the letters are official and arrive by post or appear in your Personal Tax Account, and it points customers to GOV.UK to check that a letter is genuine. If a letter reaches you by another route, check it on GOV.UK before you pay anyone. ## What Happens If You Ignore an HMRC Simple Assessment? HMRC’s Chief Customer Officer has said of the letters, "please don’t ignore it". An unpaid, unchallenged bill stays due, and HMRC can pursue it through [HMRC enforcement action](https://taxdisputes.co.uk/hmrc-enforcement-action/). For an individual, HMRC can petition for bankruptcy where the debt is £5,000 or more, usually after a statutory demand that gives 21 days to pay or dispute it, as our guide to [whether HMRC can make you bankrupt](https://windinguppetitionsolicitors.co.uk/can-hmrc-make-me-bankrupt-directors-sole-traders-bankruptcy-risks-explained/) sets out. Our article on a [recent HMRC bankruptcy petition](https://taxdisputes.co.uk/2026/08/hmrc-bankruptcy-petitions-the-carragher-case/) shows how the petition stage works, and our [bankruptcy advice page](https://windinguppetitionsolicitors.co.uk/bankruptcy-advice/) covers setting aside statutory demands and opposing petitions. Court orders over bank accounts are another route creditors use, and our guide to [frozen bank accounts and third party debt orders](https://lexlaw.co.uk/solicitors-london/bank-account-frozen-third-party-debt-order-help/) explains how they work. If you also run a company, its HMRC debts follow different rules: see our pages on [HMRC statutory demands](https://taxdisputes.co.uk/hmrc-statutory-demand/) and [HMRC winding up petitions](https://taxdisputes.co.uk/hmrc-winding-up-petitions/), and our answers on [HMRC debts and winding up petitions](https://windinguppetitionsolicitors.co.uk/hmrc-debts-and-winding-up-petitions-your-top-faqs-answered/). ## When Bad Tax Advice Led to the Bill Some simple assessments follow advice that went wrong. An accountant or adviser may have told you that no tax was due on savings or a second income, or may never have told you the income needed reporting. The bill is still yours to deal with first, and a claim against the adviser is a separate step. Our guide to [negligence claims against financial advisers](https://lexlaw.co.uk/negligence-claims-against-financial-advisers/) explains what must be shown when an adviser gave poor advice. Claims against advisers carry their own time limits, and those can begin to run before the HMRC letter arrives, so ask early. Our [guide to limitation in professional negligence claims](https://professionalnegligenceclaimsolicitors.co.uk/limitation-period-in-professional-negligence-claims/) and our [professional negligence claims page](https://professionalnegligenceclaimsolicitors.co.uk/professional-negligence-claims/) set out the rules. ## How We Can Help We act for individuals and businesses in HMRC disputes, including challenges to assessments and appeals to the tribunal. We do not offer free legal advice or legal aid, and we generally take on substantial matters, so a modest bill that a letter to HMRC and some paperwork would resolve is one you may prefer to handle yourself using the steps above. Where larger sums, a penalty or an enforcement threat are involved, see our pages on [taxation solicitors](https://lexlaw.co.uk/practice-areas/taxation-solicitors-london/), [legal representation](https://taxdisputes.co.uk/legal-representation/) and our [second opinion page](https://taxdisputes.co.uk/second-opinion/). We are dual qualified solicitors and barristers with chambers in Middle Temple, next to the Royal Courts of Justice. We offer a fixed fee advice conference with both a solicitor and a barrister, and you can start with our [case assessment form](https://taxdisputes.co.uk/legal-case-assessment/). ## Our ⭐⭐⭐⭐⭐ Client feedback: - ## 4 Year HMRC Battle Resolved > "Many thanks to the Tax Team who helped me navigate out of a four year battle with HMRC. Living abroad was a barrier in dealing with HMRC and it was immensely frustrating before I found LexLaw. Great communication, very knowledgeable, upfront in regards to cost and worth every penny in my opinion. 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You have 60 days from the date of the notice to query it, or any longer period HMRC allows (section 31AA(3) Taxes Management Act 1970). If HMRC then gives a final response you disagree with, you must appeal within 30 days after you are given notice of that response (section 31A(1)(b) and (4A)(a)). Can I pay an HMRC simple assessment in instalments? GOV.UK says you can pay in full or in smaller instalments, provided the whole bill is paid by the deadline on your letter. If you cannot clear it by then, you may be able to agree a payment plan, and HMRC will check that the plan is affordable. Our guide to Time to Pay arrangements explains the process. What if my HMRC simple assessment is wrong? Tell HMRC within the 60-day period which amounts are wrong and what they should be, and send the records that support your figures. HMRC must then give a final response that confirms the assessment, replaces it with an amended one or withdraws it without replacement (section 31AA(9)). *This article is general information and not legal advice.*