Tax Diary: February to March 2023 Deadlines That May Still Matter

This tax diary covers key tax deadlines that fell between February and March 2023 and is relevant for taxpayers who want to check whether any obligations from that period were missed.

Although these dates have passed, unresolved filing or payment issues linked to them can still lead to penalties, interest, or HMRC follow-up action.

Key UK Tax Deadlines for February and March 2023

• 1 February 2023 – Due date for corporation tax payable for the year ended 30 April 2022.
• 19 February 2023 – PAYE and NIC deductions due for month ended 5 February 2023. (If you pay your tax electronically the due date is 22 February 2023)
• 19 February 2023 – Filing deadline for the CIS300 monthly return for the month ended 5 February 2023. 
• 19 February 2023 – CIS tax deducted for the month ended 5 February 2023 is payable by today.
• 1 March 2023 – Due date for Corporation Tax due for the year ended 31 May 2022.
• 2 March 2023 – Self-Assessment tax for 2021-22 paid after this date will incur a 5% surcharge unless liabilities are cleared by 1 April 2023, or an agreement has been reached with HMRC under their time to pay facility by the same date.
• 19 March 2023 – PAYE and NIC deductions due for month ended 5 March 2023 (If you pay your tax electronically the due date is 22 March 2023).
• 19 March 2023 – Filing deadline for the CIS300 monthly return for the month ended 5 March 2023. 
• 19 March 2023 – CIS tax deducted for the month ended 5 March 2023 is payable by today.

Why Past Tax Diary Deadlines Are Still Relevant

Tax deadlines do not become irrelevant simply because time has passed. Where a return was not submitted or a payment was made late, the matter can remain open until it is resolved.

This means February and March 2023 deadlines may still affect you today if HMRC considers an obligation outstanding.

Common Obligations Around February and March

Deadlines during this period often relate to:

• Self Assessment filing and payment obligations
• VAT return submissions and payments
• PAYE and National Insurance reporting and payments

Which obligations applied will depend on your circumstances, such as whether you were self-employed, an employer, or VAT-registered and whether you were using bookkeeping services in London or managing records yourself during that period.

What Happens If a Deadline Was Missed?

If a tax deadline from February or March 2023 was missed, HMRC may have issued penalties or charged interest.

In some cases, penalties increase over time until the return is filed or the payment is made. Even where no immediate penalty was raised, HMRC may still pursue the issue later.

Why It Is Worth Reviewing Now

Some taxpayers assume older deadlines no longer matter. In practice, unresolved issues often resurface through HMRC reminders, statements of account, or compliance checks.

Reviewing whether all obligations from February and March 2023 were met can help avoid unexpected demands or enforcement action, especially where past filings were handled without professional accounting services in London.

HMRC Guidance on Late Tax Deadlines

HMRC provides guidance on late filing, late payment, and the penalties and interest that may apply on
GOV.UK.

Did You Miss Any February or March 2023 Deadlines?

Whether any action is required now will depend on which obligations applied to you at the time and whether they were handled correctly. For individuals and businesses in Hammersmith and nearby areas such as Brook Green and Stamford Brook, CIGMA Accounting can review the position and confirm whether anything remains outstanding or needs to be corrected.