If you need to complete a tax return for the 2017/18 tax year, you will need to inform HMRC by completing a form SA1 by 5th October 2018. You will need to complete a return if any of the following apply; You became a company director You receive land and property income You have taxable foreign income of more than £300 per year You receive income from a trust You have a capital gains liability (due to the sale of shares, property, etc) You have an annual income in excess of £