The deadline to submit tax returns (electronically).
You will need to submit your first Payment on Account for the tax period. If you currently owe any tax from the previous tax year, you will have to pay the balancing payment by this date.
The remainder of your tax is due in July after you make the first payment in January.
If your limited company has a year-end of 31st December, this is when your Corporation Tax payment will be due.
You must register by 5 October after the end of the tax year. For example, if you need to complete a tax return for the tax year 6 April 2019 – 5 April 2020, you must register by 5 October 2020
If you want to submit paper Self Assessment tax returns and would like to request underpayments of £3,000 or less of tax to be collected through PAYE, you will need to submit by this date.