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HMRC letter codes · Self Assessment (SA)

SA251Exit letter

Last reviewed 14 October 2026 · How Tax Letters checks its facts

In short

HMRC's Self Assessment manual forms index describes SA251 as a letter to the taxpayer explaining that HMRC no longer needs a Self Assessment (SA) return to be completed.

“Letter to taxpayer explaining that we no longer need an SA return to be completed”

GOV.UK: HMRC Self Assessment Manual, SAM002 Forms Index · checked 14 October 2026

Information, not advice: this page reports what HMRC, GOV.UK and the bodies named publish about SA251. Each fact has its source and the day it was checked beside it.

When HMRC sends it

HMRC's Self Assessment manual says that when what it calls a CY-1 tax return is captured, the computer system identifies PAYE / SA cases suitable for removal from SA and, for those cases, sends a letter (SA251) to the taxpayer and any acting agent. The manual page does not explain the label CY-1.

“When a CY-1 tax return is captured, the computer system will identify PAYE / SA cases suitable for removal from SA. … Send a letter (SA251) to the taxpayer and any acting agent (SA251 Agent) explaining that we no longer need an SA tax return to be completed.”

GOV.UK: HMRC Self Assessment Manual, SAM101040 Automatic removal of cases from SA using CY-1 return · checked 14 October 2026

HMRC's Self Assessment manual says the SA251 will be issued digitally where the customer has opted into digital notifications.

“The SA251 will be issued digitally where the customer has opted into digital notifications.”

GOV.UK: HMRC Self Assessment Manual, SAM101040 Automatic removal of cases from SA using CY-1 return · checked 14 October 2026

Free help and HMRC contacts

For Self Assessment queries about returns, payments, replacements or notices, GOV.UK's general enquiries page gives the number 0300 200 3310 and links to information about call charges. The page does not name SA251.

“Call HMRC if you have a query about: … your Self Assessment returns, payments, replacements or notices … Telephone: 0300 200 3310 … Find out about call charges”

GOV.UK: Self Assessment: general enquiries · checked 14 October 2026

Free help first

These routes are described by GOV.UK, TaxAid and Citizens Advice themselves.

  • HMRC's extra supportHMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital.
  • Someone to deal with HMRC for youYou can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms.
  • TaxAidTaxAid helps people with tax problems who cannot pay for advice. Tax Help for Older People merged with TaxAid in July 2025.
  • Citizens AdviceCitizens Advice gives confidential advice online, over the phone and in person, for free.