If the deadline of 31 January is missed, HMRC will automatically issue a £100 penalty, and will charge interest on any unpaid tax. The cost goes up again for failure to file within three months.

Whether you are an individual taxpayer or SME, it is important to gather all the right information in advance of preparing a tax return, with a number of changes to returns this year, including reporting cryptocurrency gains and a reduction in filing requirements for some high earners.