You need to file your Self Assessment return, and you can’t get in. Maybe you changed your phone number and the 2FA code goes nowhere. Maybe you can’t find your UTR number. Maybe you never registered in the first place and don’t know where to start. The deadline is getting closer, and every day you’re not filing feels like another step toward a penalty.

Don’t panic. There are three separate problems you might be facing, and the fix is different for each. This hub maps all three and links to the detailed guide for each one — work out which one you’re in, then follow the specific route.

1. The three HMRC online accounts — and which one you actually need

Before you try to fix an access problem, it helps to know what you’re actually trying to access. HMRC runs three things that people confuse:

Government Gateway is the login system. It’s your user ID (a 12-digit number) and password, plus a 2-step verification method (SMS, authenticator app, or the HMRC app). You created a Government Gateway account when you first registered for any HMRC online service. It’s the front door — without it, you can’t get into anything.

HMRC Online services are what you access after logging in through Government Gateway. Your Self Assessment section lives here, along with VAT, PAYE, and any other tax services you’ve “attached” to your account. When people say “I can’t log into HMRC,” they usually mean they can’t get through the Government Gateway login to reach their HMRC Online services.

Personal Tax Account is a specific HMRC Online service aimed at PAYE employees and pensioners. It shows your tax code, PAYE income, and any P800 refund you’re owed. If you’re self-employed, you’ll use the Self Assessment section of HMRC Online, not the Personal Tax Account — but you log into both through the same Government Gateway credentials.

The key point: you only need one Government Gateway account. If you’ve lost access to it, you need to recover that specific account — you can’t just create a new one and attach your existing tax records to it, because the identity verification step will recognise you already have an account and block you. For the full recovery sequence when you’re locked out, see our locked out of Government Gateway guide.

2. If you’re locked out of your HMRC account

This is the most common access problem, and it usually has one of two causes: you changed your phone number and the 2FA code goes to the old number, or you changed your name (e.g. through marriage) and identity verification fails because your new photo ID doesn’t match what HMRC holds. If you have both problems at once, you’re in a circular lockout — but it has a break point.

The break point is this: you can update your name with HMRC by phone or post without logging in. Call Income Tax general enquiries on 0300 200 3300, tell them you’ve changed your name, and they’ll update your records. Once that propagates (a few days), your new-name passport or driving licence will match the identity verification system, and you can recover your 2FA access using the “Get help” link at the login screen. If that fails, call the online services helpline on 0300 200 3600 — not the Self Assessment helpline, which handles tax questions but not login problems.

If you’re being fined for late filing while locked out, request a paper return (form SA100) from the Self Assessment helpline on 0300 200 3310. Filing by post stops the daily penalties while you recover online access. For the full step-by-step recovery sequence — including the exact order to do things if you have both a name change and a phone number change — see our locked out of Government Gateway guide.

3. If you’ve lost your UTR number

Your UTR (Unique Taxpayer Reference) is a 10-digit number HMRC assigned you when you first registered for Self Assessment. You need it to file, to pay, and to communicate with HMRC about your tax. Without it, you’re stuck.

Before contacting HMRC, check the places it’s likely to be: previous tax returns and tax calculations, HMRC letters (especially your SA250 welcome letter and SA302 calculations), your Government Gateway account (if you can log in), your accountant or filing service, and your bank transactions (it’s the payment reference for Self Assessment payments). If none of those work, call the Self Assessment helpline on 0300 200 3310 — they’ll post your UTR to your registered address within 10 working days. HMRC cannot email it for security reasons, and if you’ve moved house without updating your address, update that first. For every method of finding your UTR, including what to do if the deadline is days away, see our lost UTR number guide.

4. If you’ve never registered for Self Assessment

If you’ve never registered, you don’t have a UTR yet — you need to register first. Go to gov.uk/register-for-self-assessment, fill in the online form with your National Insurance number and the date you started self-employment (or became a landlord), and HMRC will post you a UTR within 10 working days.

The official deadline is 5 October after the end of the tax year in which you became self-employed or started earning above the £1,000 trading allowance. If you missed it, register now — late registration is better than no registration, and the penalty regime for late registration is completely different (and much kinder) than the one for late filing. If you owed no tax for the years you missed (e.g. your income was below the Personal Allowance after the £1,000 trading allowance), the penalty is £0. For the full breakdown of what actually happens when you register late, see our didn’t know you needed to register guide.

5. What to do if you’ve lost everything at once

If you’ve never registered, don’t have a Government Gateway account, and can’t find any HMRC correspondence — you’re starting from scratch, but the process is straightforward:

  1. Register for Self Assessment at gov.uk/register-for-self-assessment. You’ll need your National Insurance number.
  2. Wait for your UTR to arrive by post (up to 10 working days).
  3. Create a Government Gateway account at gov.uk/log-in-register-hmrc-online-services. You’ll need to verify your identity using your passport or driving licence.
  4. Attach your Self Assessment to your new Government Gateway account once you have your UTR.
  5. File your return online.

If you’re doing this in January with the deadline days away, your UTR won’t arrive in time. Register immediately, file as soon as the UTR arrives (even if it’s after 31 January), and appeal any late filing penalty on the grounds that you registered as soon as you realised you needed to file but HMRC’s postal delivery took longer than expected — postal delay in receiving your UTR can be a reasonable excuse. Keep evidence: screenshot your registration confirmation, note the date, and keep the envelope your UTR arrives in (it shows the postmark date). For the appeal process, see our appeal an HMRC penalty guide.

6. How to file while waiting for credentials

If you’re waiting for your UTR or for your Government Gateway access to be restored and the deadline is approaching, you don’t have to just wait and accumulate penalties. You can file by post using a paper return (form SA100):

  1. Call the Self Assessment helpline on 0300 200 3310 and request a paper return for the tax year you need to file.
  2. HMRC will post the form to you.
  3. Complete it and post it back to HMRC (keep your proof of posting — it’s free from the Post Office).
  4. Filing by post stops the daily late-filing penalties from the date HMRC receives your return.

Paper returns have a different filing deadline — 31 October instead of 31 January for online returns. But if you’re filing late because you were waiting for credentials, the key is that you filed as soon as you reasonably could. The paper return is a stopgap to stop penalties while you sort out online access; once you have your UTR and Gateway access back, you can file online for future years.

The bottom line

  1. Work out which problem you have — locked out of your account, lost your UTR, or never registered. The fix is different for each.
  2. If you’re locked out, the break point is updating your name by phone (0300 200 3300) without logging in, then recovering 2FA via the “Get help” link or the online services helpline (0300 200 3600).
  3. If you’ve lost your UTR, check your documents first, then call 0300 200 3310 — they’ll post it within 10 working days.
  4. If you’ve never registered, register now at gov.uk — the 5 October deadline matters, but late registration with no tax owed means no penalty.
  5. If you’ve lost everything, start from scratch: register, wait for UTR, create Government Gateway account, attach Self Assessment, file.
  6. If the deadline is looming, request a paper return on 0300 200 3310 — it stops the daily penalties while you sort out online access.

The 10-day postal wait is the biggest frustration in all of these scenarios. The sooner you start the process, the sooner you’ll have what you need to file.

For the full list of Self Assessment deadlines, penalties, and payment options, see our Self Assessment deadlines and payment hub.

For the full recovery sequence when you’re locked out of Government Gateway, see our locked out of Government Gateway guide. For every method of finding a lost UTR, see our lost UTR number guide. For what happens when you register for Self Assessment late, see our didn’t know you needed to register guide. If you’ve missed the filing deadline, see what to do when you miss the Self Assessment deadline. If you’ve received a penalty you want to challenge, see how to appeal an HMRC penalty.

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