UK delays mandatory digital amendments to Company Tax Returns to April 2028

Original Company Tax Returns are already generally filed electronically, but amendments may still be made by correspondence. HMRC says the future rule will apply to amendments submitted on or after 1 April 2028 regardless of the accounting period, subject to defined exceptions and fallback routes. This is a policy timetable, not enacted legislation or a final technical specification.^[1][2]

Exceptions and fallback routes

HMRC intends exceptions for amendments connected with enquiries or litigation; complex changes spanning companies or accounting periods; cases where the original filing software is unavailable; and HMRC system or other technical limitations. Existing exemptions applying to original online returns should continue for amendments, and a non-digital route should remain where an HMRC systems issue prevents online filing by a statutory deadline.^[1][2]

Why the timetable moved

Consultation responses supported digitisation but raised legacy-return, software, file-size and systems concerns. HMRC says the later start allows time to define the exceptions and publish guidance. Detailed treatment of historic returns, long accounting periods, unavailable software and fallback evidence remains outstanding.^[1][2]

Prescribed computations remain separate

HMRC has put prescribed Corporation Tax computations into a longer co-creation process. It plans consultation on a completed prescription in early 2027 but has not fixed implementation dates. The government also does not intend immediate enforcement directly against Corporation Tax software providers, with that position to be revisited alongside wider software-standards work.^[1]

Action for companies and agents

Tax and software teams should move planning assumptions from 1 April 2027 to 1 April 2028, identify cases likely to need exception or fallback workflows and monitor forthcoming guidance. The response announces no immediate change to statutory amendment windows.^[1][2]