With HMRC reporting just a week before the deadline that over 3m people had still not filed their returns (just under one third of the people in self-assessment), there will be plenty of people who have not yet submitted their forms.

If you have missed the deadline, unless you have a reasonable excuse or had only registered to complete a return in the last three months, HMRC will be issuing you with a £100 late filing penalty, on top of any tax you owe.

In addition to that, you have just extended HMRC’s enquiry window. Usually HMRC have 12 months from the date of submission to enquire into your tax return. However, where the return is submitted late, this is extended to the next ‘quarter day’ which will be the 30 April, 31 July, 31 October or 31 January, depending on when you submit the form.

Pau