Approximately six million (52%) of the expected 11.5 million returns for 2017 and 2018 have already been filed, but this still leaves roughly 5,542,000 outstanding, according to HMRC.
Of the returns already filed 88% were completed online with almost 800,000 still being filed on paper.
“It is encouraging that around 52% of taxpayers have already completed their Self Assessment tax returns,” said Mel Stride, financial secretary to the Treasury.
“With less than one month to go before the deadline, there are still many people that need to act now,” he added.
Following the festive break, figures from the Revenue showed that the number of tax returns completed over Christmas and Boxing Day broke the 10,000 mark, with 2,616 and 8,465 being filed on each day respectively.