When an accountant files your company accounts: what stays with the director

acrenvo.com/guides/accountant-files-your-company-accounts, last reviewed 1 November 2026

Daniel is fictional. He is a director of a small limited company, and an accountant has prepared and filed its accounts for years. When he read that Companies House will take accounts only through software from April 2028, his first thought was that it was the accountant’s problem. Much of it is, but some parts stay with him as a director, and this guide sets out which, from what Companies House and GOV.UK have published.

What the change means when an accountant files

Companies House’s rule reaches companies whose accounts are filed by a professional as well as those whose directors file themselves. From 1 April 2028, all companies must file their accounts using commercial software. This applies to companies who file accounts themselves, and companies who use a professional (such as an accountant) to file their accounts.

For Daniel, the practical change happens in his accountant’s office, because the accountant is the one sending the accounts. Even so, Companies House asks directors to check. If you already use a professional, check they are prepared for the upcoming changes to accounts.

What stays with the director

Handing the filing to an accountant does not hand over the responsibility for it, and Companies House says so in the same sentence that suggests hiring one. If you do not want to buy commercial software, you can hire a professional (such as an accountant) to file on your behalf. A professional can help you file and stay compliant - but you’re still legally responsible for your company’s accounts, records and performance.

The accounts also still need a director’s name on them, whoever prepares them. GOV.UK says: “The balance sheet must have the name of a director printed on it and must be signed by a director.”

Identity checks are personal to each director, though an accountant can help with them. You can ask an Authorised Corporate Service Provider (ACSP) to verify your identity on your behalf. For example, an accountant or solicitor. This is also known as a Companies House authorised agent. If you have an existing accountant or solicitor (or any other AML-supervised professional), you can ask them if they are registered with Companies House as an ACSP. The guide to Companies House identity verification covers the dates and the personal code.

Sharing the company authentication code

An accountant who files through software uses the company’s authentication code, which stands in for a director’s signature. The company authentication code is a 6 digit alphanumeric code issued by Companies House to each company. The code is used to authorise information filed online and is the equivalent of a company officer’s signature.

That is why Companies House asks directors to be careful about who holds it. You should treat your company authentication code with the same care as your bank card PIN. Anyone who knows your code is able to change your company’s details online. Among its advice on looking after the code, GOV.UK lists this point: only share your code with someone you trust to file information for your company.

If Daniel ever changes the code himself, his accountant needs to know straight away, or the next filing will fail. You must tell anyone else who files online for your company (such as an accountant) if you change your code. They will not be able to use the old company authentication code once it has been changed.

The guide to getting ready to file company accounts by software explains how to request the code and how long it takes to arrive.

If you change accountant

A change of accountant is one of the moments Companies House names for changing the code, so that the old firm can no longer file for the company. GOV.UK’s advice is to change your code if it’s known by someone who’s no longer authorised to file for your company (such as staff who’ve left your company, or your previous accountant).

After the change, the new code goes to the new accountant, for the reason above: once a code is changed, the old one stops working for anyone who still has it. Sign in to Companies House WebFiling to change or cancel your code. You can change your code to something more memorable, but do not make it easy to guess.

If the accounts are filed late

If the accounts go in late because of a delay at the accountant’s end, Companies House warns that an appeal on that ground may not succeed. Your appeal may not be successful if, among other reasons:

• it was your accountant’s (or anybody else’s) fault

That is a good reason to agree a date with the accountant well before the deadline, especially in the first year through software. The guide to company accounts and Company Tax Return deadlines sets out the deadlines, both bodies’ penalties and the appeal routes.

Questions worth asking your accountant before April 2028

These are not questions Companies House sets. Each one follows from a point it makes, and the answers tell a director whether anything is left to do before 1 April 2028.

• Whether their software can file the company’s type of accounts in Inline eXtensible Business Reporting Language (iXBRL) at Companies House. GOV.UK notes: “Not all software supports the iXBRL tagging you’ll need to file digital accounts.”
• Whether it can send corrected accounts, because GOV.UK names software as a route for amended accounts only if you used it to file your annual accounts and your software allows you to submit corrected accounts. The guide to correcting company accounts explains why that matters after 1 April 2028.
• Whether they hold the company’s current authentication code.

Our company filing hub links to GOV.UK’s two lists of software, and our monthly counts of the software used to file company accounts show which products companies file with today, and our counts of how many accountancy firms use each accounts software package show which packages accountancy practices rely on.

Questions about an accountant filing your company accounts