HMRC has restarted automatic Corporation Tax late-filing penalty notices after a temporary system pause. The penalties themselves never stopped. Companies that filed CT600 returns late during the pause can still get delayed notices, and the higher penalty rates introduced from 1 April 2026 now apply in full.
HMRC Automatic Penalty Notices Are Running Again
HMRC has confirmed its issuing automatic Corporation Tax late-filing penalty notices again. Notices were paused temporarily while HMRC updated its systems to apply the higher penalty rates introduced from 1 April 2026.
This matters for UK company directors. A missing notice never meant a penalty had been cancelled. Companies that filed after their deadline still owe the penalty, and some may now receive notices later than expected.
What Are the New Corporation Tax Late-Filing Penalties?
The fixed penalties have doubled.
A Company Tax Return filed one day late triggers a £200 penalty. If the return stays outstanding after three months, another £200 can apply.
Repeated late filing costs far more. If a company files late for three consecutive accounting periods, each £200 fixed penalty can rise to £1,000. That means a return more than three months late could add up to £2,000 in fixed penalties under the repeat-filing rules.
Longer delays bring further costs. At six months late, HMRC can estimate the Corporation Tax owed and add a penalty worth 10% of the unpaid tax. At 12 months, another 10% penalty can apply.
Who Needs to Pay Attention?
These rules affect any company required to submit a Company Tax Return, including small business owners that made a loss or owe no Corporation Tax. A zero-tax bill doesn’t remove the duty to file, and it doesn’t remove the risk of fixed penalties.
Dormant companies need extra care. If HMRC has formally accepted a company as dormant, it may not need to submit a CT600 unless HMRC asks for one. Directors should check their company’s actual filing status rather than assume that no trading means no return is needed.
Late Payment Can Add Another Cost
Late filing and late payment are two separate issues.
HMRC’s current Corporation Tax late-payment interest rate stands at 7.75%. That means a company that files late and also pays late can face filing penalties on top of interest on the unpaid tax.
If cash flow is tight, directors should still aim to file their CT600 on time. Filing on time can avoid late filing penalties, even if the full tax payment isn’t ready by the payment deadline, though it’s worth reviewing your cash flow position early to plan around the payment deadline.
HMRC and Companies House Are Separate
Companies House accounts and HMRC Corporation Tax returns are separate filing obligations. Meeting one deadline doesn’t satisfy the other.
Private companies can also face Companies House penalties for late annual accounts. These currently range from £150 to £1,500 depending on the delay, with steeper consequences for repeated late filing.
What Should UK Companies Do Now?
Directors should check whether any CT600 returns remain outstanding, especially if they expected a penalty notice during HMRC’s temporary pause but never received one.
Review upcoming Corporation Tax payment dates and Companies House deadlines too. If a penalty notice arrives, don’t ignore it. A company with a genuine reasonable excuse may be able to appeal, but it must file the outstanding return first, and if the notice relates to a wider HMRC compliance check or investigation, it’s worth getting advice before responding.
How Lanop Can Help
HMRC restarting automatic notices is a clear reminder that delayed enforcement doesn’t mean cancelled liability.
At Lanop. we help UK companies review Corporation Tax deadlines, prepare and file CT600 returns, clear outstanding compliance issues, and understand their options when they can’t pay tax on time, all as part of proactive tax planning.
Acting early can stop a £200 penalty from turning into a much larger and more expensive compliance problem. Contact Lanop today to review your Corporation Tax filing position before the next deadline.
