What to do when you get a letter from HMRC

For many people, an envelope marked HMRC triggers immediate anxiety. The instinct is often to put it aside and deal with it later — which can make things more complicated. In reality, the vast majority of HMRC letters are routine communications that either require a simple response or no action at all. Understanding what they are asking for removes most of the stress.

Do not ignore HMRC letters

The most important rule is to open the letter and read it promptly. Ignoring correspondence from HMRC does not make it go away — it can result in penalties, interest charges, or enforcement action that would not have occurred if the letter had been addressed in the first instance. Even if you cannot deal with it immediately, read it and note any deadline.

Common types of HMRC letter

A notice of coding (a P2 notice) tells you what tax code HMRC is using for you. If your tax code looks wrong, you should contact HMRC or check your Personal Tax Account online. Common reasons for incorrect tax codes include a change of job, starting or stopping a benefit in kind, or HMRC holding outdated information about your income.

A tax calculation (P800) is sent when HMRC thinks you have either overpaid or underpaid tax. If you have overpaid, the letter will explain how you will receive a refund. If you have underpaid, it will explain the amount owed and how it will be collected — usually through your tax code in a future year rather than an immediate payment.

A self-assessment reminder is sent if you are registered for self-assessment. It reminds you to file a return and pay any tax owed by the relevant deadline. Missing these deadlines results in automatic penalties, so act promptly.

An enquiry letter means HMRC wants to check some aspect of a tax return or income. This does not necessarily mean anything is wrong — HMRC conducts routine enquiries. You should respond within the timeframe given and, if the enquiry involves complex tax matters, consider seeking advice from a qualified accountant.

Check the letter is genuine

HMRC scam letters and emails do exist. Legitimate HMRC letters will be addressed to you by name, will not ask for payment by gift card, and will not demand immediate payment under threat of arrest. If you are unsure whether a letter is genuine, check the HMRC website for guidance on identifying scam communications before responding or calling any number listed on the letter.

How to respond

If a response is required, the letter will tell you how — by post, phone, or through your Personal Tax Account online at GOV.UK. Setting up a Personal Tax Account is free and makes it easier to manage HMRC correspondence, check your tax record, and update your details. Most routine matters can be resolved there without needing to call.

How Ask Fin can help

The Tax Relief tool in Ask Fin helps you estimate pension contribution tax relief, which can affect your tax position. If you are unsure about whether you might owe tax or be eligible for a refund, speaking with a qualified accountant or HMRC directly is the right next step.