How do I stop filing Self Assessment returns?
Tell HMRC as soon as possible, using its online Self Assessment cessation service, or by phone or post to the Self Assessment general enquiries team. gov.uk gives three reasons: you have stopped being self-employed, you no longer rent out property, or you no longer pay the High Income Child Benefit Charge.
Figures checked against gov.uk on . General information, not tax advice.
Why timing matters
gov.uk says HMRC needs time to review your request before the 31 January Self Assessment deadline and that you may have to pay a penalty if you do not tell it early enough. Do not leave the request until the last week of January.
How to tell HMRC
The online route needs you to sign in, and you can create sign-in details the first time you use it. If you cannot use the online service, phone or write to HMRC's Self Assessment general enquiries team. Agents cannot use the online service and should phone or write to HMRC's agent line.
HMRC then confirms whether you still need to send a return, including for a year in which you stopped part-way through, so keep your records for the part of the year you traded.