31 January 2017 This is the final deadline for online tax returns. If you file your tax return late, you will face a fine of minimum £100 up-to £1600 from HMRC. For the tax year ended 5 April 2016, the final deadline for self-assessment tax returns is: 31 January 2017 – online.
Who Has to Submit Tax Return?
Over nine million people need to complete a self-assessment tax return (SA100 or SA200) and submit this to their tax office. You'll need to fill in a tax return if:
a business partner
director of a limited company
your income (or your partner’s) was over £50,000 and one of you claimed Child Benefit
Pensioner with an annual income of £100,000
you have a pre-tax investment income of £10,000
you're a minister of religion
you're a trustee or representative of someone who has died