1 November 2025 – Due date for Corporation Tax due for the year ended 31 January 2025.

19 November 2025 – PAYE and NIC deductions due for month ended 5 November 2024. (If you pay your tax electronically the due date is 22 November 2025.)

19 November 2025 – Filing deadline for the CIS300 monthly return for the month ended 5 November 2025. 

19 November 2025 – CIS tax deducted for the month ended 5 November 2025 is payable by today.

1 December 2025 – Due date for Corporation Tax payable for the year ended 28 February 2025.

19 December 2025 – PAYE and NIC deductions due for month ended 5 December 2025. (If you pay your tax electronically the due date is 22 December 2025).

19 December 2025 – Filing deadline for the CIS300 monthly return for the month ended 5 December 2025. 

19 December 2025 – CIS tax deducted for the month ended 5 December 2025 is payable by today.

30 December 2025 – Deadline for filing 2024-25 self-assessment tax returns online to include a claim for under payments to be collected via tax code in 2026-27.

Source:HM Revenue & Customs | 07-10-2025
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Aitch
Aitch is the visionary founder and CEO of CIGMA Accounting Ltd, a boutique accounting and tax advisory firm with offices in Wimbledon and Farringdon, London. With over a decade of experience, Aitch has built a reputation for strategic tax planning, complex HMRC compliance resolution, and innovative AI-powered accounting workflows that help SMEs, landlords, and high-net-worth clients streamline their finances. His expertise spans corporation tax, inheritance tax planning, R&D tax credit claims, capital allowances, and international tax matters, making him a trusted advisor for clients seeking to minimise tax liabilities while staying fully compliant. Aitch is passionate about bridging traditional accounting principles with cutting-edge digital solutions, allowing businesses to operate efficiently and future-proof their financial systems. Through CIGMA, he aims to make accounting smarter, faster, and more human-centric - empowering clients to focus on growth while staying ahead of regulatory changes.