Can I correct my tax return?

Congratulations.  You hit the filing deadline.  Then you realise a week or a month later you got your UK taxes wrong- you missed some income out, you included income you should not, or you forgot to fill in the non-residence section and you should have done.  Should I panic?

The answer is no.  Accidents happen and the UK system allows for it.  You can submit an amended tax return up to one year after the deadline for submission of the original return. So or the year to 5 April 2025, the deadline for electronic filing was 31 January 2026, so you have until January 2027 to fix it.  Paper has different deadlines - especially if you are not UK resident I really do not recommend using paper returns.

What you do need to be is clear its an amended return - so if you are using an expert or software to do it make sure they indicate / you check the box it is an amended return.  

You may be charged interest on tax you underpaid but better that then HMRC asks questions later if it checks your return and then hits you with penalties.