Previously, both paper and online self assessment tax returns had to be filed by 31 January. That deadline remains in place for online tax returns only.
HMRC are advising people filing paper returns to start thinking about the information they need now. This includes a completed P60, self-employment accounts, records of savings and investments, and details of any untaxed income.
To register for self assessment online you can visit the HMRC website, which calculates tax automatically and gives immediate online acknowledgement.
Any tax due has to be paid by 31 January for both paper and online returns once filed.
Help and advice on completing your Self Assessment tax return is available on the HMRC website at gov.uk or from the Self Assessment helpline on 0845 9000 444.