A record 9.5m self-assessment tax returns were completed on time, the highest figure since HMRC started.

Last year only 6.9m people had completed their tax return by the deadline.

Some 80 per cent of assessments this year were completed online where the busiest day was 31 January.

Over 445,000 were received online that day including 37,460 between 4-5pm, more than one every six seconds.

David Gauke, exchequer secretary to the Treasury, said: “I’m delighted so many people filed their tax returns online this year. The record number proves it’s quick, easy and secure to do.

“HMRC has always been clear they want returns not penalties, so it is good news that over 90 per cent of all returns were submitted on time.”

While the 31 January deadline remained unchanged, HMRC decided there would be no penalties for online returns received by midnight on 2 February.

This was due to earlier industrial action by almost 7,000 staff at HMRC contact centres.

For those who did not file their tax return on time, there is an automatic penalty of £100 which increases through the year and is applicable even if there is no tax to pay.

The maximum penalty for late returns is £1,600 if the self-assessment is not returned for longer than a year.