Who can sign and file a company tax return (CT600)?

In short: The CT600 declaration is made by the company's proper officer (the company secretary, or whoever acts as secretary) or another person the company authorises, such as a director. An agent who prepares and sends the return makes it themselves (GOV.UK: Company Tax Return obligations). A director signs the accounts for the board. Taxley prepares and files the CT600 for £39.95 with micro-entity accounts, then files the accounts at Companies House once the return is paid and the accounts are finished.

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Key facts (checked on 8 October 2026)

Who can sign the CT600 declaration?

The company's proper officer, or any other person the company authorises, signs the declaration on a Company Tax Return (CT600) (HMRC manual CTM00530). An agent who prepares and submits the return makes the declaration; when an agent only submits it, the proper officer or another authorised person makes it (GOV.UK: Company Tax Return obligations).

The requirement itself is in the Finance Act 1998: a company tax return must include a declaration by the person making the return that, as far as they know, it is correct and complete (FA 1998 Sch 18 para 3). When the company completes and submits its own return, HMRC's guidance says the person making it completes the declaration on the company's behalf (GOV.UK: Company Tax Return obligations). The Taxes Management Act 1970 lets a company act through anyone with its express, implied or apparent authority (TMA 1970 s.108), so an authorised director qualifies. On the form, box 975 holds the declarant's name, box 980 the date and box 985 their status (HMRC: Company Tax Return guide). The rest of the filing checklist is in our guide on what you need to file a CT600.

Who is the company's proper officer for Corporation Tax?

The company secretary, or the person acting as secretary. If a liquidator or administrator has been appointed, that person is the proper officer instead. A private company doesn't have to appoint a secretary; where there is none, a director or a person the directors authorise can do the secretary's tasks.

The Taxes Management Act 1970 says a company acts through its proper officer or, unless a liquidator has been appointed, through any person with the company's express, implied or apparent authority to act for it (TMA 1970 s.108). Subsection (3) defines the proper officer as the secretary or person acting as secretary, or the liquidator or administrator once one is appointed. The Companies Act 2006 says a private company isn't required to have a secretary, and in a private company without one, anything the secretary would do may be done by a director or by a person the directors authorise (Companies Act 2006 s.270). GOV.UK adds that a company secretary can be a director but not the company's auditor, and that the directors stay legally responsible for the company even when there is a secretary (GOV.UK: Appoint directors and a company secretary).

Can an accountant or tax agent file the CT600 for the company?

Yes. An accountant or other tax agent registered with HMRC can file a client company's CT600 through commercial software, using the agent's own sign-in. If the agent prepares and submits the return, the agent makes the declaration. If the agent only sends it, the company's proper officer or another authorised person makes the declaration.

HMRC's Corporation Tax for Agents online service lets an agent file clients' Company Tax Returns using commercial software, and a new tax agent must register with HMRC first (GOV.UK: Corporation Tax for Agents). Before an agent submits a return, HMRC says the agent must keep a copy of the information and receive confirmation from the proper officer or another authorised person that it is correct and complete (GOV.UK: Company Tax Return obligations). Using an agent doesn't move the responsibility: GOV.UK says you're still legally responsible for your own tax, and you must check the information and tell the agent it's correct before they submit it (GOV.UK: Authorising an agent).

Whose Government Gateway sign-in sends the return?

The company's own Government Gateway user ID and password, with Corporation Tax added, when the company files for itself. GOV.UK says the company gets its own user ID when it is registered, and a director can't use a personal Government Gateway ID. An agent sends a client's return with the agent's own sign-in instead.

GOV.UK's company registration guidance says you'll need to create a Government Gateway user ID and password for the company, and that you cannot use your personal ID (GOV.UK: Register your company). The sign-in identifies who is sending; it doesn't decide who declares, so a secretary or director can declare and the company's ID still sends the return. Sign-in details aren't shared with an agent: GOV.UK says not to give your sign-in credentials to your agent, and that an agent must not use a client's credentials to sign in to any account (GOV.UK: Change or remove your tax agent's authorisation). Our guide on the Government Gateway user ID for Corporation Tax explains where to find a lost ID and how the agent sign-in differs.

Who approves and signs the company's annual accounts?

The board of directors approves the annual accounts, and one director signs them on the board's behalf, on the balance sheet. The accounts filed at Companies House must state the name of the director who signed, and a secretary can't sign in a director's place.

The Companies Act 2006 says a company's annual accounts must be approved by the board of directors and signed on behalf of the board by a director, with the signature on the balance sheet (Companies Act 2006 s.414). Accounts prepared under the small companies regime need a statement above that signature: that they are micro-entity accounts, or that they follow the small companies provisions. The copy of the balance sheet delivered to Companies House must state the name of the person who signed it for the board, for a micro-entity (s.443A) and for other small companies (s.444). Under s.414(4), a director who knew the accounts didn't comply, or was reckless about it, and failed to take reasonable steps to stop their approval commits an offence.

For board approval, the model articles for private companies let a sole director take decisions alone (model articles, article 7). With two or more directors, a decision can be majority at a meeting or unanimous, with every eligible director indicating agreement by any means, including a signed written resolution (model articles, article 8). Check your own articles, as they may differ.

Who can file the accounts at Companies House?

The directors are responsible for delivering the accounts, and Companies House guidance lets anyone the company trusts with its 6-character authentication code file them online, such as a director or an accountant. Companies House treats the code as the equivalent of a company officer's signature. A Government Gateway sign-in can't be used for Companies House filing.

The Companies Act 2006 puts the duty on the directors to deliver the accounts and reports to the registrar for each financial year (Companies Act 2006 s.441). Companies House says the authentication code authorises information filed online and is needed to file online or through commercial software. Commercial software also needs a presenter ID and presenter authentication code, and you can't use your Government Gateway account to send information to Companies House. Companies House advises sharing the code only with someone you trust to file for the company, and changing it if a former accountant or member of staff knows it (GOV.UK: Company authentication codes). Companies House says it will later bring in identity verification for people who file, and businesses that file for clients will need to register as authorised agents (GOV.UK: When you need to verify your identity). If the letter has gone missing, see our guide to a lost Companies House authentication code; the filing steps are in how to file company accounts with Companies House online.

Who does each filing task, from approval to Companies House?

Each task has its own rule. The board approves the accounts and a director signs them; the proper officer or an authorised person declares the CT600, unless an agent prepares and sends it; the company's own Government Gateway ID sends a self-filed return; and the authentication code authorises the Companies House filing. The decision table sets out each one.

Signing the accounts is a Companies Act task for a director, while the CT600 declaration is a tax task for the proper officer or an authorised person (HMRC manual CTM00530). The same person can do both, but the law doesn't require it. A company secretary who isn't a director can make the tax declaration, yet a director still has to sign the balance sheet (Companies Act 2006 s.414).

How does it work for a company with two directors, one abroad?

Worked example: Priya and Tom direct a small property company that files micro-entity accounts, uses the model articles and has no secretary. Tom lives abroad. Both agree the accounts by email, Priya signs the balance sheet, Priya declares the CT600 as a director, and the company's own Government Gateway ID sends the return.

Priya emails the final accounts to Tom, and both agree in writing to approve them. That is a unanimous decision of the directors, which the model articles allow by any means (model articles, article 8), so no meeting is needed, and GOV.UK says directors don't have to live in the UK (GOV.UK: Appoint directors). Priya then signs the balance sheet for the board, and her name appears on the copy filed at Companies House (Companies Act 2006 s.443A). With no secretary, Priya acts for the company under s.270 and makes the CT600 declaration, entering her name, the date and "Director" as her status in boxes 975 to 985. The return goes to HMRC under the company's Government Gateway ID, and the accounts go to Companies House with the company's authentication code.

Two variations change who declares. If the company had a secretary, Sam, who isn't a director, Sam could make the CT600 declaration as proper officer, but Priya or Tom would still sign the balance sheet (TMA 1970 s.108). An accountant who prepared and submitted the return would make the declaration and send it with the practice's agent sign-in; if the accountant only submitted Priya's return, Priya would declare it and confirm to the accountant that it is correct and complete (GOV.UK: Company Tax Return obligations).

How does Taxley handle the declaration, the sign-in and the accounts signature?

Taxley asks who is declaring, their role (director, secretary or authorised person) and the date the accounts were approved, and puts the signing director's name on the balance sheet. A company filing for itself sends the return with its own Government Gateway sign-in, and an accountant using agent mode sends it with the practice's agent sign-in.

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, fills in what it knows and lets you change it. It suggests names from the directors listed at Companies House, and you can change any name it fills in. When the declarant is a secretary or authorised person, Taxley asks which director approved the accounts; a director who declares can name a different director who signed. The date the accounts were approved is also the declaration date, and it can't be before the period end or in the future. Taxley shows HMRC's declaration statement and its warning about false information, and you tick the declaration before paying, £39.95 with micro-entity accounts or £129 with small-company accounts.

To file with HMRC, you then enter the company's own Government Gateway user ID and password; Taxley never keeps the password. In agent mode, an accountant enters the practice's HMRC agent sign-in, and Taxley shows that the declaration is made by the person named on the return, on the company's behalf; a practice can record the client's agent authorisation on the client page, as Taxley can't check it with HMRC. You save the company's Companies House authentication code once in its details, and Taxley files the accounts at Companies House once the return is paid and the accounts are finished. Taxley is software, not a tax agent: it doesn't give tax advice or file the confirmation statement, and the person declaring stays responsible for the figures. Take the 30-second check to see whether Taxley fits your company.

Frequently asked questions

Can a company secretary sign the company tax return?

Yes. The secretary, or whoever acts as secretary, is the company's proper officer for tax, and HMRC's manual says the proper officer or another authorised person should sign the declaration (HMRC manual CTM00530). A secretary who isn't a director can't sign the accounts, though.

Does the director who signs the accounts also have to declare the CT600?

No. The Companies Act needs a director's signature on the balance sheet (s.414), while the tax declaration can come from the proper officer or another authorised person. One director can do both, but different people may.

Can I give my accountant the company's Government Gateway password?

No. GOV.UK says not to give your sign-in credentials to your agent, and that an agent must not use a client's credentials (GOV.UK: agent authorisation). An accountant files with their own agent sign-in after the company authorises them.

What happens if the declaration on a CT600 is wrong?

HMRC warns that giving false information or concealing any part of the company's profits or tax can lead to prosecution of both you and the company, and an inaccurate return can bring a penalty (GOV.UK: Company Tax Return obligations).

Can a director who lives abroad sign the company accounts?

Yes. GOV.UK says directors don't have to live in the UK, though the company needs a UK registered office (GOV.UK: Appoint directors). The Companies Act needs only that a director signs the balance sheet for the board.

General information, not personalised tax or accounting advice.