Corporation Tax Late Filing Penalties: A UK Guide for 2026

Could filing one day late leave your company facing a £200 penalty, even if it has no Corporation Tax to pay? For returns with a filing date on or after 1 April 2026, corporation tax late filing penalties have doubled. The amount can increase further if the return remains overdue or your company has a history of late filing.

It’s easy to confuse the filing deadline with the payment deadline, but they are different. A Company Tax Return is generally due 12 months after the end of its accounting period, while Corporation Tax for most companies is payable earlier, after 9 months and 1 day. Missing either deadline has separate consequences, so paying on time does not prevent a late-filing penalty.

This guide explains which penalty rules may apply, when additional charges can arise and what to do if your return is overdue. It also covers the 2026 changes, when an appeal may be possible and how organised bookkeeping and accounts preparation can help you keep future filing dates on track.

What counts as a late Corporation Tax return, and which deadline matters?

A Corporation Tax return is late if HMRC receives it after the filing deadline that applies to the company. The return, commonly submitted using form CT600, reports the company’s Corporation Tax position for an accounting period. Filing late is separate from paying late: one concerns when HMRC receives the return, the other when the company pays any tax due.

This distinction matters because a company may face corporation tax late filing penalties even if it has paid its tax on time. For a general introduction to the tax, see this overview of Corporation Tax in the United Kingdom.

When is a Company Tax Return due?

For most companies, the filing deadline is 12 months after the end of the accounting period. For example, if the period ends on 31 March 2025, the usual filing deadline is 31 March 2026. Check the accounting-period dates held by HMRC and the filing date stated in any notice to deliver a return. If HMRC’s notice gives a different date, follow that date rather than relying on a general example.

This is not the same as the deadline for paying Corporation Tax, which usually falls earlier. For the payment timetable and the rules that apply to your company, read our separate guide on when to pay Corporation Tax.

Company Tax Returns go to HMRC. Annual accounts are a separate filing, submitted to Companies House under its own requirements and timetable. Preparing or filing one does not automatically complete the other. Organised records and statutory accounts preparation can support the work needed to prepare a return, but the company still needs to meet each filing obligation.

Does filing late mean the tax payment was late too?

No. Filing and payment are separate obligations, with separate deadlines and consequences. A company could submit its CT600 after the filing deadline but pay the tax by its payment deadline. It could also file the return on time but pay Corporation Tax after the payment deadline.

In short, a late return is received after its filing date; a late payment is made after its payment date. Paying on time does not submit a missing return or remove a filing penalty. Equally, filing on time does not settle tax due. If you’re unsure which date has been missed, check the accounting period, HMRC’s filing notice and the company’s payment records separately.

Corporation Tax late filing penalties in 2026: what changes from 1 April?

The penalty rules depend on the filing date that applies to the return, not simply when you read about them. HMRC’s increased charges apply to Company Tax Returns with a filing date on or after 1 April 2026. Check the deadline for the specific return and compare it with that date before working out which schedule may apply.

Which 2026 rules apply to my company?

Use the deadline for the return in question to identify the relevant schedule. The table summarises the standard penalties, with the repeated-late-return rules explained separately below. Read the official HMRC guidance on Corporation Tax penalties alongside any penalty notice.

Return filing date	Initial penalty	At 3 months late	At 6 and 12 months late	Source
Before 1 April 2026	£100	Additional £100	At 6 months, HMRC may estimate the tax due and charge 10% of unpaid tax; a further 10% may apply at 12 months.	HMRC, Corporation Tax penalties
On or after 1 April 2026	£200	Additional £200, making £400 in total	At 6 months, HMRC may estimate the tax due and charge 10% of unpaid tax; a further 10% may apply at 12 months.	HMRC, Corporation Tax penalties

These are filing penalties. They can apply even if the company has no Corporation Tax to pay, is dormant or has made a loss.

How can penalties increase the longer a return is overdue?

The fixed charges apply first, while later penalties can be based on unpaid tax. For returns with a filing date on or after 1 April 2026, the standard escalation is £200 when one day late, a further £200 at three months, then 10% of unpaid tax at six months and a further 10% at 12 months.

Repeated late filing can increase the fixed penalty. After three consecutive late returns, the initial penalty rises to £1,000; if all three are more than three months late, the penalty for the third return rises to £2,000. These increased figures apply to the 2026 schedule, so don’t use them to calculate a return governed by the earlier rules.

Identifying the correct schedule is the first step. If you need support with your company’s tax compliance and filing responsibilities, discuss your Corporation Tax compliance.

Late filing versus late payment: understand the separate Corporation Tax consequences

A Company Tax Return and a Corporation Tax payment are separate obligations. The return tells HMRC how the company’s Corporation Tax liability has been calculated; the payment settles any tax due. Filing and payment can therefore each be late independently, with different consequences.

This distinction is central to understanding corporation tax late filing penalties. A payment record does not count as submitting a return, and an on-time return does not mean the tax has been paid on time. Check each obligation against its own deadline and review HMRC’s records and notices for both.

What happens if the return is late but the tax was paid?

The company may still receive a late-filing penalty, even if it paid the tax by the payment deadline. Evidence of payment shows that the liability was settled, but it does not replace the CT600 or automatically cancel a penalty for an outstanding return. Submit the missing return as soon as possible, then check any penalty notice separately.

If a return remains outstanding for six months, HMRC may estimate the Corporation Tax due and issue a tax determination. For returns subject to the 2026 rules, a penalty of 10% of unpaid tax may then apply. This is linked to the late-filing regime and the estimated unpaid tax; it is distinct from interest charged because a payment itself was late.

What if both the return and Corporation Tax payment are late?

Both consequences may apply at once. Late filing can trigger fixed and, where relevant, tax-geared penalties. Late payment generally results in interest on the unpaid Corporation Tax. HMRC’s rate was 7.75% per annum on 9 January 2026, calculated daily from the payment due date until the tax is paid; interest rates can change. The rules described here do not include a separate flat-rate penalty for late Corporation Tax payment.

Review the return’s filing status and the company’s payment account independently. Check whether HMRC has issued a filing penalty, a tax determination or a statement showing interest, and make sure any amount due is paid. Don’t assume that resolving one issue automatically settles the other.

For the applicable payment timetable, refer to the separate guide on when to pay Corporation Tax. It explains the payment deadline without confusing it with the return-filing date.

What to do if your Corporation Tax return is already late

An overdue return needs prompt attention. A clear sequence helps you deal with the filing obligation and any penalty notice separately. First establish which accounting period is affected and prepare an accurate return for HMRC. Filing the return does not guarantee that a penalty will be cancelled, but it is a required step before appealing.

1. Identify the period. Check the company’s accounting-period dates and HMRC’s notice to deliver a return. Confirm which Company Tax Return is missing and its filing deadline.
2. Prepare and submit the overdue return. Bring the relevant records together and file the return as soon as you can. Don’t wait for an appeal decision before submitting it.
3. Review HMRC’s notices. Check the penalty amount, the return period, the date of the notice and any instructions or response deadline. Also review the company’s tax account separately for any outstanding tax or interest.
4. Consider whether to appeal. If you believe there was a reasonable excuse for missing the deadline, follow HMRC’s current appeal procedure and explain the circumstances with supporting evidence.

Should I file the return before appealing?

Yes. HMRC’s guidance instructs companies to submit the outstanding Company Tax Return before appealing a late-filing penalty. File accurate information promptly rather than holding the return back while you decide what to include in an appeal. Then follow the instructions on the penalty notice and check HMRC’s latest appeal process, including the deadline for making your appeal.

Can I appeal a Corporation Tax late filing penalty?

A reasonable excuse means circumstances that help explain why the company could not meet its filing obligation on time. Whether an excuse is accepted depends on the facts; an appeal is not automatically successful. Explain what happened, how it affected the company’s ability to file and what you did once you could act. Keep dated records, such as relevant correspondence or other documents, to support your account. HMRC’s guidance says an appeal should generally be made within 30 days of the penalty notice, so check the notice and current instructions carefully.

Coombs Chartered Accountants provides Corporation Tax compliance support to help businesses manage their filing responsibilities. Support can help you organise the return and review the steps ahead, but it cannot guarantee that HMRC will cancel a penalty.

Contact us about your overdue Corporation Tax return to discuss tax-compliance support.

Prevent future Corporation Tax late filing penalties with a reliable process

A dependable process makes filing dates visible well before the return is due. Record each company’s accounting-period end date, HMRC filing deadline and Corporation Tax payment deadline in one compliance calendar. Assign a named person to oversee each task, with a reminder before the deadline so the return does not depend on a last-minute prompt.

Current bookkeeping helps too. When transactions are recorded and supporting documents are organised throughout the year, there is less to reconstruct when year-end accounts and the Company Tax Return are prepared. This cannot guarantee that corporation tax late filing penalties will always be avoided, but it gives the company a clearer, more manageable route to meeting its obligations.

What should a company include in its annual tax compliance checklist?

Keep the key dates and responsibilities together, but track each obligation separately:

• Accounting-period start and end dates, and the Company Tax Return filing deadline.
• The Corporation Tax payment deadline, shown separately from the filing date.
• The named person responsible for gathering records, reviewing the return and confirming submission.
• Dates for collating and checking records early enough to follow up missing information.
• A place to save filing confirmations and HMRC correspondence alongside the records for the relevant accounting period.

A reliable routine is simple: prepare early, monitor both deadlines and respond promptly to HMRC notices. Review the calendar when company responsibilities change, and update it as soon as an accounting period or filing deadline is confirmed.

How can professional accounts and tax support help?

Organised bookkeeping, statutory accounts preparation and tax compliance support can help bring financial records and filing tasks into a consistent process. Accounts preparation helps assemble the year-end financial information; tax compliance support helps manage the related tax-return requirements. Agreeing responsibilities and keeping records in order can make it easier to spot missing information before it delays preparation.

Coombs Chartered Accountants supports businesses with accounts preparation and tax compliance. The aim is to make filing responsibilities clearer and more organised, not to promise that a statutory penalty can be removed.

Discuss your accounts and tax compliance needs.

Put a clear Corporation Tax filing process in place

The key to managing corporation tax late filing penalties is knowing which filing-date rules apply to your return, then acting promptly if a deadline has passed. Keep the return-filing and tax-payment dates separate: meeting one does not automatically meet the other. If a return is overdue, establish the accounting period, submit it, review HMRC’s notice and assess whether there may be grounds to appeal.

For future periods, record deadlines and responsibilities in one compliance calendar, and keep bookkeeping and supporting records up to date. This makes it easier to prepare year-end accounts and tax returns in good time. An appeal may be considered where there is a reasonable excuse, but HMRC decides each case on its circumstances.

Coombs Chartered Accountants provides statutory accounts preparation and tax compliance support to businesses in Manchester, Stockport, Wilmslow and Alderley Edge. Discuss your accounts and tax compliance needs and take a practical step towards a more organised filing process. With clear dates, reliable records and defined responsibility, future deadlines can feel much more manageable.

Frequently Asked Questions

How much is the penalty for filing a Corporation Tax return late in 2026?

For a return with a filing date on or after 1 April 2026, the initial penalty is £200 once it is one day late, with another £200 if it remains unfiled for three months. At six months, HMRC may estimate the tax due and charge 10% of unpaid tax, with a further 10% possible at 12 months. Returns due before that date use the previous rates, so identify the deadline for the specific return first.

What happens if a Company Tax Return is more than six months late?

After six months, HMRC may issue a tax determination, estimating the Corporation Tax due, and add a penalty of 10% of unpaid tax. If the return remains outstanding for 12 months, a further 10% of unpaid tax may be charged. The estimate is not a substitute for submitting the return. File it promptly, then review the determination and any penalty notice to understand the amounts HMRC has assessed.

Do Corporation Tax late filing penalties increase from 1 April 2026?

Yes. The higher rules apply to Company Tax Returns with a filing date on or after 1 April 2026, rather than simply because the return is dealt with after that date. Under the new schedule, the initial fixed penalty is £200 and another £200 may apply at three months. Check the filing deadline for your specific return to establish which schedule governs it.

Should I file my Corporation Tax return before appealing a penalty?

Yes. HMRC instructs companies to submit the outstanding Company Tax Return before appealing a late-filing penalty. Don’t wait for an appeal decision before filing: submit accurate information promptly, then follow the appeal instructions on the penalty notice. Keep a copy of the return submission confirmation and supporting evidence about the delay. Check the latest HMRC procedure and notice details, including the time limit for making an appeal.

Can I be penalised for filing late if I paid my Corporation Tax on time?

Yes. Filing the Company Tax Return and paying Corporation Tax are separate obligations, so paying by the payment deadline does not count as filing the return or automatically cancel a filing penalty. The company may still face corporation tax late filing penalties if HMRC receives the return after its filing deadline. Check the return’s status and payment records separately, and submit any outstanding return as soon as possible.

Are Companies House accounts filing penalties the same as Corporation Tax return penalties?

No. Annual accounts filed with Companies House and a Company Tax Return submitted to HMRC are separate filings, with distinct requirements and penalty rules. Meeting one deadline does not automatically meet the other. Keep both filing dates in the company’s compliance calendar and save submission confirmations for each. Coombs Chartered Accountants provides accounts preparation and tax compliance support to businesses in Manchester, Stockport, Wilmslow and Alderley Edge.