Self Assessment Tax Returns: time limits for Self Assessment procedure
Ordinary time limit of four years
The normal time limit for making an assessment of any kind is not later than four years following the end of the tax year to which it relates. After the four-year time limit has passed tax can only be assessed by means of an HMRC assessment (see SALF411).
In certain exceptional circumstances the self assessment time limit may be extended where there has been a determination of tax under section 28C (see Time limits for determinations and subsequent self assessments in SALF209).