If you are self-employed, and obliged to submit a self-assessment tax return, you must keep your tax records for at least five years after the 31 January submission deadline of the relevant tax year. For example, if you sent your 2017-18 tax return online by 31 January 2019, you must keep your records until at least the end of January 2024. Records for this purpose includes those relating to personal income etc.
If you send your tax return more than four years after the deadline, you will need to keep your records for fifteen months after you submit your tax return.
If you keep your tax records on a computer, make sure you have sufficient backups of your data to meet these requirements. If you change software during the record retention period, you may need to print relevant reports if you are unable to maintain access to data backups.
If you run your business as a limited company you must keep records for six years from the end of the last company financial year they relate to, or longer if:
they show a transaction that covers more than one of the company’s accounting periods,
the company has bought something that it expects to last more than six years, like equipment or machinery,
you sent your Company Tax Return late, or
HMRC has started a compliance check into your Company Tax Return.
If you are not in business, the minimum period is 22 months after the 31 January filing deadline and at least 15 months after filing if later.