Online submission deadline for 2018/19 self-assessment tax returns Jan 31^st, 2020
Balance of any Tax, national Insurance and student loan Owed to HMRC for 2018/19 must be paid. Jan 31^st, 2020
Payment of Capital Gains Tax for 2018/19 Jan 31^st, 2020
Deadline for making Gift Aid donations to carry back to 2018/19 (provided tax return not submitted earlier). Jan 31^st, 2020
Form P46 (Car) filed for the quarter ended 5 January 2020. Feb 2^nd, 2020
Corporation Tax Returns filed by companies with 31 March 2019 year end. Mar 31^st, 2020

End of Current Tax Year Apr 05^th, 2020
2^nd Payment of Account of Tax for 2019/20 due to HMRC Jul 31^st, 2020
Deadline to advice HMRC that you need to register for Self-Assessment for the 2019/20 Tax Year. Oct 05^th, 2020
Deadline for Filing Paper Income Tax Return with HMRC Oct 31^st, 2020
Deadline for Filing Income Tax Return with HMRC if yoy want any Tax Collected through your PAYE Coding (Under £3,000) Dec 30^th, 2020