My accountant hasn't filed my company accounts or tax return: what now?

In short: The company and its directors stay legally responsible even when an accountant was hired, so check the Companies House register and HMRC's business tax account, chase the accountant in writing with a firm date, and get the authentication code and Gateway sign-in ready to file yourself if needed (GOV.UK: Directors' responsibilities). Taxley prepares and files the CT600 for £39.95 with micro-entity accounts, and files the accounts at Companies House once the return is paid and the accounts are finished.

Take the 30-second check to see whether Taxley fits your company, or work out your dates with the Corporation Tax deadline calculator.

Key facts (checked on 10 October 2026)

Who is legally responsible if the accountant hasn't filed?

The company and its directors. Companies Act 2006 section 441 puts the duty to deliver the accounts to Companies House on the directors, and HMRC's notice to deliver makes the company file a Company Tax Return (CT600). GOV.UK says a director can hire an accountant but is "still legally responsible" for the company's records and accounts.

GOV.UK says a director who doesn't prepare and file the accounts and Company Tax Return may be fined, prosecuted or disqualified (GOV.UK: Running a limited company). Companies House's penalty guidance says a director is personally responsible for delivering the accounts before the time allowed runs out (Companies House: Late filing penalties). Two separate consequences follow a missed accounts deadline. The company becomes liable to a civil penalty (Companies Act 2006 s.453), and every director in office at the deadline commits an offence, with a defence only for a director who took all reasonable steps to get the accounts filed in time (Companies Act 2006 s.451).

The duty to file the CT600 also stays with the company. GOV.UK says a company that gets a notice to deliver must file a return, even with a loss or no tax to pay, and that you can either get an accountant to prepare and file it or do it yourself (GOV.UK: Company Tax Returns). The law makes the company, not its adviser, liable to the late filing penalty (FA 1998 Sch 18 para 17). A missed date often has an ordinary cause, such as records still with the company or an illness, so the first step is to ask what is outstanding and agree a date in writing.

How do you check what has actually been filed?

Look at the company's page on the free Companies House register, which shows filed accounts as document images and when the next accounts are due. For the CT600, sign in to the company's HMRC business tax account, whose Corporation Tax card can show whether a return is still to complete. Then ask the accountant for HMRC's acknowledgement.

GOV.UK says anyone can see a company's details, including its document images, for free (GOV.UK: Get information about a company). Companies House's guidance suggests using the same service to check when the accounts are due (Companies House: Late filing penalties). The register shows nothing about the CT600, which goes to HMRC.

HMRC's guide says a company that uses an agent can still use its business tax account to check what's happening, and that a tax card may show whether you have a return to complete, with links to return information and, for most taxes, any late filing penalties (HMRC: How to use your business tax account). You sign in with the company's own Government Gateway user ID, which has up to 12 characters (GOV.UK: HMRC online services). Ask the accountant for the filed copies and HMRC's submission receipt too; our guide on whether HMRC has received your CT600 explains what a receipt shows.

What should you do first, depending on how much time is left?

Work from the earliest deadline, which is usually the accounts at Companies House, due 9 months after the year end, because the CT600 isn't due until 12 months. With months to spare, a written timetable from the accountant may be enough; with weeks left, prepare to file yourself; once a deadline has passed, file as soon as you can.

HMRC's Compliance Handbook expects you to explain what you need the other person to do, set deadlines and check progress regularly, reminding them where appropriate. It adds that someone who realises several months before a deadline that their agent can't file should be able to instruct a replacement in time (HMRC manual CH160700). Companies House posts the authentication code to the registered office, which can take up to 10 working days, and warns not to wait until the accounts are due (GOV.UK: Company authentication codes). Corporation Tax is paid separately from filing, and HMRC may charge interest if you don't pay on time (GOV.UK: Pay your Corporation Tax bill).

What would the penalties be if nothing gets filed?

For a private company with a 31 December 2025 year end that files nothing, Companies House charges £150 to £1,500 depending on lateness, and HMRC charges £200, or £400 once the return is over 3 months late, plus 10% or 20% of unpaid tax. With £4,000 of tax unpaid, the total reaches £2,700 by January 2028.

Taxley's example company filed on time last year and owes £4,000 of unpaid Corporation Tax. Its accounts were due at Companies House on 30 September 2026, 9 months after the year end (GOV.UK: Accounts and tax returns). The tax was due on 1 October 2026, 9 months and 1 day after the period ended (GOV.UK: Pay your Corporation Tax bill), and the CT600 is due on 31 December 2026, 12 months after it ended (GOV.UK: Company Tax Returns). Each row assumes the accounts and the return are both filed on the date shown.

Taxley's worked example: year end 31 December 2025, nothing filed yet

The Companies House column uses the private company bands: £150 up to 1 month late, £375 from 1 to 3 months, £750 from 3 to 6 months and £1,500 after that (GOV.UK: Penalties for late filing of annual accounts). HMRC's flat penalty is £200 if the return arrives within 3 months after the filing date, or £400 after that, for returns due from 1 April 2026 (GOV.UK: penalty increases). A return still missing 18 months after the period ends, here on 30 June 2027, adds 10% of the tax then unpaid, or 20% if the return arrives more than 2 years after the period ends, here after 31 December 2027 (FA 1998 Sch 18 para 18). So £4,000 × 10% = £400 and £4,000 × 20% = £800.

The totals leave out interest on the unpaid tax, and three things would make the cost higher. Next year's Companies House penalty doubles if those accounts are late too (GOV.UK: Penalties for late filing). HMRC's flat penalties rise to £1,000 and £2,000 for a third late return in a row (FA 1998 Sch 18 para 17). And once a return is 6 months late, HMRC can write with its own estimate of the tax, called a determination, which can't be appealed; you pay the tax and file the return (GOV.UK: Company Tax Returns penalties). Try your own dates in the Corporation Tax late filing penalty calculator.

Is "my accountant let me down" a reasonable excuse?

Sometimes for HMRC, rarely for Companies House. GOV.UK lists relying on someone else to send your return, when they didn't, as something that may count as a reasonable excuse for HMRC. HMRC's manual adds that you must have taken reasonable care. Companies House says an appeal blaming your accountant may not succeed.

GOV.UK's reasonable excuse page includes "you relied on someone else to send your return, and they did not", and adds that you must send the return as soon as you're able to (GOV.UK: Reasonable excuses). HMRC's Compliance Handbook says delegating the task isn't an excuse on its own. You need to be able to tell HMRC what you did to make sure the obligation was met, and examples that may count include an agent's illness or bereavement and a new adviser delayed in getting paperwork from the previous one (HMRC manual CH160700). The return comes first: GOV.UK says you must file the Company Tax Return before appealing a late filing penalty (GOV.UK: Company Tax Returns penalties), and you usually have 30 days from the date the penalty was issued (GOV.UK: Disagree with a penalty).

Companies House is stricter. GOV.UK says an appeal may not succeed if it was your accountant's, or anybody else's, fault (GOV.UK: Penalties for late filing). Companies House's own guidance says an appeal resting only on relying on your accountant, or the accountant's illness, is unlikely to succeed; its discretion covers unforeseen events at a critical time, such as a fire destroying records just before the deadline (Companies House: Late filing penalties). Our guides on Companies House late filing penalties and filing a CT600 late cover the appeal routes.

What do you need to file the accounts and CT600 yourself?

Five things besides the year's figures: the Companies House authentication code, the company's own Government Gateway user ID and password, its 10-digit UTR, last year's accounts and tax computation, and any losses brought forward. The accountant may hold the last two, so ask for them in writing early; the codes come by post.

The authentication code is a 6-character code that acts as an officer's signature for online filing; it can be sent to a home address if you can't get post at the registered office (GOV.UK: Company authentication codes). The same page says to change the code if someone no longer authorised to file, such as a previous accountant, knows it, and to tell anyone who still files for you. The CT600 goes in under the company's own Government Gateway user ID; GOV.UK says a director can't use a personal one (GOV.UK: Set up a private limited company). The UTR is on HMRC letters such as notices to file, or can be requested online and is posted to the registered address (GOV.UK: Find your UTR number).

Last year's accounts give the comparative figures, and last year's computation shows the losses carried forward, which this year's computation must identify (HMRC: Company Tax Return guide). The business tax account's "manage account" menu lets you add, view or change a tax agent (HMRC: How to use your business tax account). For the full list of records to request, use our handover pack for changing accountant; our guides to finding the Gateway user ID and a lost authentication code help with the sign-ins.

Can Taxley file the accounts and CT600 if your accountant hasn't?

Yes, for many small companies. A director can prepare the Company Tax Return (CT600) and micro-entity, small, abridged or dormant accounts in Taxley, file the return with HMRC, and file the accounts at Companies House once the return is paid and the accounts are finished. Some accounts still have to be filed another way.

Taxley (taxley.co.uk), UK online software that prepares and files the Company Tax Return (CT600) with HMRC and the annual accounts with Companies House, charges one fee per return: £9.50 for a dormant company, £39.95 with micro-entity accounts or £129 with small-company accounts, which also covers filing the accounts at Companies House. You file the CT600 with the company's own Government Gateway user ID and password, and Taxley never keeps the password. To file at Companies House, you press "File accounts at Companies House" on the filing page, with the company's 6-character authentication code saved in its details.

The limits matter when an accountant has been involved. Taxley doesn't file at Companies House accounts you uploaded instead of its own, accounts for a period Companies House already has that weren't filed through Taxley, or first accounts when the return's period doesn't start on the company's date of incorporation; you file those yourself. If an earlier year's accounts are still missing at Companies House, Taxley asks you to file those first. Last year's figures and losses brought forward come from the company's Taxley return for the period just before (for losses, once it is filed); if the accountant filed last year, you enter them from last year's accounts and computation. Taxley doesn't file confirmation statements, doesn't pay the tax and isn't tax advice. Accountants can use its agent mode with their own agent Gateway login. Take the 30-second check to see whether Taxley fits your company, or see the price for your company.

Frequently asked questions

Who pays the penalty if my accountant files late?

The company. Companies House's penalty falls on the company under section 453 of the Companies Act 2006 (legislation.gov.uk), and HMRC's late filing penalty is charged to the company that had to deliver the return. Any claim against the accountant depends on your agreement with them.

Will Companies House give more time because my accountant is late?

Only for an event outside your control, applied for before the deadline passes. GOV.UK's example is a fire that destroyed company records (GOV.UK: Apply to extend your accounts filing deadline), and Companies House grants an extension only if the reasons are exceptional.

Does filing the accounts at Companies House also file the CT600?

No. GOV.UK says you file the accounts with Companies House and the Company Tax Return with HMRC (GOV.UK: Filing accounts and tax returns). Each has its own deadline and its own penalties, so check both before assuming the job is done.

Should I pay the Corporation Tax before the return is filed?

Yes. Payment is usually due 9 months and 1 day after the accounting period ends, before the 12-month filing deadline, and HMRC may charge interest on late payment (GOV.UK: Pay your Corporation Tax bill). Paying doesn't file the return, which you still need to send.

General information, not personalised tax or accounting advice.