This is in addition to the £100 late filing penalty for missing the deadline for filing self assessment tax returns online by 31 January. An estimated 1.1 million taxpayers missed the 31 January deadline this year, giving HMRC a tidy £110m in revenue.

The £10 penalties accrue on a daily basis so they can be punitive and quickly mount up.

Additional penalties are also levied for late payment of the tax due – 5% of the tax due at 30 days, six months, and 12 months – along with interest charged on the unpaid tax at 7.75%, the highest rate in over 20 years. 

With 1 May less than a week to go, it is crucial to file a tax return or try to contact HMRC to discuss your situation as there can be exceptional circumstances where a penalty is waived.

Lucy Woodward, partner at Saffery, said: ‘Taxpayers should do everything in their power to ensure they complete their returns and pay any outstanding tax due as soon as possible, given interest is being incurred each day on the unpaid tax at a rate of 7.75% per annum, and especially before the end of April and the substantial step change in the size of the penalty levied by HMRC.

‘Taxpayers who are struggling to complete their returns for whatever reason can still make use of the self assessment helpline after HMRC reversed its decision in March to close the helpline between April and September in favour of online support services, following an outcry from many customers.

‘Taxpayers should also seek professional advice where necessary, and if there are any concerns about being able to pay the tax due, raising it with HMRC as soon as possible may mean some arrangements can be made to help make the payment more manageable.’