If previous years are anything to go by, hundreds and thousands of people will have missed yesterday’s tax return deadline.

Late filers face an automatic penalty of £100 unless they have a ‘reasonable excuse’.

HMRC’s website lists the following as ‘reasonable excuses’:

• your partner or another close relative died shortly before the tax return or payment deadline
• you had an unexpected stay in hospital that prevented you from dealing with your tax affairs
• you had a serious or life-threatening illness
• your computer or software failed just before or while you were preparing your online return
• service issues with HMRC online services
• a fire, flood or theft prevented you from completing your tax return
• postal delays that you couldn’t have predicted

This year, HMRC is allowing people who’ve been affected by the recent flooding more time to submit their returns.

The tax authority says taxpayers should contact them as soon as they receive the penalty notification as the ‘reasonable excuse’ allowance only exists for a short time after the deadline and the return must be submitted as soon as possible after the deadline.

An HMRC spokesperson said: “We trust the Great British public, we believe taxpayers are honest unless there is strong evidence otherwise.”

Snowballing fees

Chas Roy-Chowdhury, head of taxation at the Association of Chartered Certified Accountants (ACCA), said it’s best to get your tax return filed as soon as possible as the penalties rise with time and the overdue payments accrue interest.

If you still have not filed three months after the deadline, you’ll start to clock up an automatic £10 per day penalty, up to a maximum of £900.

After six months, in addition to the penalties above, you’ll have to pay a further £300 or 5% of the tax liability, whichever is higher.

If you’ve still not filed a year after the deadline, there’s a further £300 penalty or up to 100% of the tax due as a penalty.