Flow Shorts: Corporation tax late filing penalties have doubled
- Stephen Kelly
- Jul 20
- 1 min read
Updated: 14 hours ago
Corporation tax late filing penalties have gone up for the first time since they were introduced in 1998. The new amounts apply where a company's filing date falls on or after 1 April 2026 - in practice, that means accounting periods ending on or after 1 April 2025.
What a late return now costs:
£200 if it arrives within three months of the filing date, up from £100
£400 if it is later than that, up from £200
£1,000 and £2,000 respectively where it is the third accounting period in a row filed late, up from £500 and £1,000
Tax-geared penalties on top are unchanged: 10% of the unpaid tax if the return is more than 18 months late, rising to 20% if it arrives more than two years after the end of the accounting period.
Two things worth knowing. HMRC paused its automatic penalty notices while it updated its systems, restarting them in July 2026 - so a quiet spring was not a reprieve, and the penalty arises whether or not a notice has landed yet. And Finance Act 2026 gives HMRC a new power to change these amounts by regulations rather than by a new Act, with Commons approval needed only for increases above inflation. Expect them to move again.
The practical point has not changed, it just costs more to ignore. Get the CT600 in on time - and if a period has already slipped, file it before the three-month line rather than after.
If you would like us to take corporation tax filings off your desk, get in touch with the Flow team.
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