Corporation Tax Fines Doubled in 2026. Is Your Clients’ Filing to Date?

From 1 April 2026, HMRC doubled all fixed late filing penalties for Corporation Tax returns. This is the first meaningful increase since the penalties were introduced in 1998. The change affects every incorporated business with a filing date on or after that date, regardless of whether any tax is actually owed. For accountants managing a portfolio of limited companies, the message is straightforward: a client who was borderline compliant before April is now paying twice the price for the same mistake.

What are the new corporation tax late filing penalty amounts?

The penalty structure has been doubled across all four tiers:

Situation	Previous penalty	New penalty (from 1 April 2026)
Return filed late (first or second time)	£100	£200
Return more than 3 months late (first or second time)	£200	£400
Third consecutive late return (one day late)	£500	£1,000
Third consecutive late return (more than 3 months late)	£1,000	£2,000

These are fixed penalties. They apply even where a company has no corporation tax liability at all. Dormant companies, newly incorporated entities, and businesses that have simply had a quiet year are all caught. HMRC confirmed the change was announced at Budget 2025 and legislated through Schedule 18 of the Finance Act 1998 as amended. The government expects the measure to raise £45 million in 2026/27, rising to £70 million per year by 2030/31.

Why has HMRC doubled these penalties now?

The original penalties were set in 1998 and had never been revised. According to HMRC’s own policy paper, inflation had eroded their real value to roughly half what they were worth when introduced. In other words, late filing had become progressively cheaper in real terms over nearly three decades, and the behavioural deterrent had been almost entirely lost.

The doubling is explicitly designed to restore that original deterrent effect, not to generate windfall revenue. That framing matters, because it signals that HMRC views timely filing as a compliance baseline, not an aspirational standard.

Which of your clients are most at risk from the new fines?

The clients most likely to be caught out fall into several categories.

Companies that have slipped by one or two months in previous years now face a materially higher bill for the same behaviour
Clients with complex year-end positions who habitually request extensions to gather information are at heightened risk if those requests aren’t tracked carefully
Dormant companies are a particularly common blind spot: with no trading activity and no tax due, it can be easy to overlook the filing obligation entirely, but the penalty applies regardless
Practices that manage company secretarial and tax deadlines across separate systems (or, worse, in spreadsheets) are most vulnerable to something slipping. A single missed filing date on a third consecutive late return now triggers a £1,000 fine before any tax-geared penalty is even considered.

How can accountants track corporation tax deadlines reliably across a client portfolio?

Deadline tracking at scale is a practice management and compliance challenge, not just a diary management one. The practices best insulated from this change are those using integrated software that links company secretarial obligations, tax return deadlines, and client communication in a single workflow.

Inform Direct by Bright is built for exactly this kind of oversight. It tracks Companies House obligations, confirmation statement deadlines, and filing histories across a portfolio of companies from one dashboard.
For the tax return side, BrightTax by Bright provides a unified view of CT600 filing deadlines across all clients, with automated reminders that flag upcoming and overdue returns before HMRC’s clock starts running.
Used together, they close the gap between company secretarial and tax compliance that is most often where late filings originate.

If you’re reviewing your current setup, our guide to simplifying Companies House compliance covers the practical steps for moving away from manual tracking, and our post on avoiding Companies House penalties is worth sharing with clients who manage their own filing.

What should accountants do right now?

There are three immediate steps worth taking before the next filing wave.

Run an audit of your client portfolio to identify any companies that filed late in either of the past two accounting periods. Those clients are already in the repeat-offender window, a single late return now costs them £1,000, not £500. They need to know this.
Check whether any clients have upcoming filing deadlines in the next 60–90 days and confirm that information-gathering is on track. The most common cause of late corporation tax returns is not negligence, it’s waiting too long for client records, bank statements, or year-end adjustments. Build that lead time into your workflow now.
Review whether your current software gives you a single, reliable view of every client’s filing position. If you’re managing deadlines across multiple disconnected systems, this penalty increase is a practical reason to consolidate. How much does processing annual accounts cost your practice? is a useful starting point for evaluating that question.

How does Inform Direct by Bright compare to alternatives for managing company secretarial compliance?

For practices choosing dedicated company secretarial software, the main alternatives to Inform Direct by Bright are TaxCalc Company Secretarial, IRIS Company Secretarial, and Diligent Entities. Standalone tools from TaxCalc and IRIS offer solid functionality but require separate workflows for practices already using Bright for payroll and accounts. For firms that want a connected compliance picture across every obligation, Inform Direct by Bright is being built on to close that gap.

This content may have been developed with the assistance of AI tools. Content is reviewed by a member of the Bright team before publication. Guidance on legislation can be obtained from your industry body.