1 June 2026 - Due date for corporation tax due for the year ended 31 August 2025.

19 June 2026 - PAYE and NIC deductions due for month ended 5 June 2026. (If you pay your tax electronically the due date is 22 June 2026).

19 June 2026 - Filing deadline for the CIS300 monthly return for the month ended 5 June 2026. 

19 June 2026 - CIS tax deducted for the month ended 5 June 2026 is payable by today.

1 July 2026 - Due date for corporation tax due for the year ended 30 September 2025.

6 July 2026 - Complete and submit forms P11D return of benefits and expenses and P11D(b) return of Class 1A NICs.

19 July 2026 - Pay Class 1A NICs (by the 22 July 2026 if paid electronically).

19 July 2026 - PAYE and NIC deductions due for month ended 5 July 2026. (If you pay your tax electronically the due date is 22 July 2026).

19 July 2026 - Filing deadline for the CIS300 monthly return for the month ended 5 July 2026. 

19 July 2026 - CIS tax deducted for the month ended 5 July 2026 is payable by today.