Avoid any penalties and interest and ensure you submit your Self Assessment Tax Return online to HM Revenue and Customs for the tax year ended 5 April 2017 by the 31 January 2018.
You also need to make your Self Assessment  balancing payment for tax year 2016/17, and make the first payment on account to HM Revenue and Customs for tax year 2017/18 by 31 January 2018.
