End of corporation tax financial year.
End of CT61 quarterly period.
Filing deadline for corporation tax return self-assessment form CT600 for period ended 31 March 2020 to be submitted to HMRC.
Deadline for filing your company tax return is 12 months after your accounting period for corporation tax ends.
Corporation tax payment due for year end 31 May 2020, for those companies not liable to pay their liability by instalments.