1 August 2026 – Due date for Corporation Tax due for the year ended 31 October 2025.

19 August 2026 – PAYE and NIC deductions due for the month ended 5 August 2026. (If you pay electronically, the due date is 22 August 2026.)

19 August 2026 – Filing deadline for the CIS300 monthly return for the month ended 5 August 2026.

19 August 2026 – CIS tax deducted for the month ended 5 August 2026 is payable by today.

1 September 2026 – Due date for Corporation Tax due for the year ended 30 November 2025.

19 September 2026 – PAYE and NIC deductions due for the month ended 5 September 2026. (If you pay electronically, the due date is 22 September 2026.)

19 September 2026 – Filing deadline for the CIS300 monthly return for the month ended 5 September 2026.

19 September 2026 – CIS tax deducted for the month ended 5 September 2026 is payable by today.