AI agents for business finance: what they can and can't do
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The short answer
You can set up Corporation Tax at the same time as you register the company with Companies House; if you do not, you add Corporation Tax to the company's business tax account with HMRC. GOV.UK's company set-up guidance gives the window as within 3 months of starting to do business. The first accounts often cover more than 12 months, which means two Company Tax Returns and two payment deadlines.
Who pays Corporation Tax
GOV.UK says Corporation Tax is paid by UK limited companies, foreign companies with a UK branch or office, and clubs, co-operatives and other unincorporated associations. A company that is not UK resident but has a UK office or branch pays only on profits from its UK activities. GOV.UK also notes you do not get a bill: the company works out what it owes and pays it.
Two ways to register
- At incorporation. When you register the company with Companies House you can set up Corporation Tax in the same process.
- Afterwards. If you did not, add Corporation Tax services to the company's business tax account. You will need the company's Unique Taxpayer Reference (UTR), which HMRC sends after incorporation; see what a UTR is and when a company gets one.
The timing rule
The deadline runs from when the company starts to do business, not from incorporation. GOV.UK's company set-up guidance gives it as within 3 months of starting to do business. That line was indexed on the page in October 2026 but did not display when we fetched it, so confirm it on GOV.UK before you rely on the exact wording.
Keep evidence of the date business started, such as the first contract, invoice or hire. A company that has been incorporated but has done nothing may be dormant for Corporation Tax; see what a dormant company still files.
Why the first year has two returns
An accounting period for Corporation Tax cannot be longer than 12 months, but a company's first accounts usually are longer. GOV.UK's example: a company set up on 11 May 2024 with an ARD of 31 May 2025 has first accounts of 12 months and 3 weeks. It needs two returns:
| Tax period (GOV.UK example) | Payment deadline |
|---|---|
| 11 May 2024 to 10 May 2025 | 11 February 2026 |
| 11 May 2025 to 31 May 2025 | 1 March 2026 |
In both cases the payment deadline is nine months and one day after the tax period ends. Each return covers its own period, and the Company Tax Return itself has a later filing date than the payment. GOV.UK also says which returns you file depends on whether you started trading on the day the company was set up or later.
A worked timeline
Example only: Segun incorporates on 2 September 2026 but only signs his first customer contract on 14 November 2026. His business starts in November, so he registers for Corporation Tax well before mid-February 2027, and the first tax period begins when trading starts. His first accounts run to 30 September 2027 (the last day of the month of the first anniversary). Because the tax period starts in November, it is under 12 months, and he may file a single return for it, with payment due nine months and one day after it ends.
What to check first
- Did you tick Corporation Tax when you incorporated? If unsure, check the business tax account.
- When did the company start to do business? Write the date down with evidence (first invoice, contract, hire).
- Has HMRC sent the UTR to the registered office? Post to an overseas director can be slow; make sure someone checks the UK address.
- Does the first accounts period exceed 12 months? If so, expect two returns.
After registration
Once registered, the company's cycle is set by its accounting periods. For each one it works out its profit, pays any Corporation Tax by the payment deadline and files a Company Tax Return. Companies House says the joint online accounts and Company Tax Return service closed on 31 March 2026, so the return now goes through commercial software or an agent. Keep the UTR, the company registration number and the business tax account login together; you will need all three each year.
Non-resident directors
A company incorporated in the UK is generally UK resident for tax, even if its directors live in Nigeria, but where a company is managed from can raise residence questions in both countries; see UK company managed from Nigeria: tax residence risk. Registration is the same either way: the company registers for Corporation Tax with HMRC.
For what happens at Companies House over the same period, see first UK company accounts: deadlines and penalties.
Where Pryme fits
Corporation Tax is easier to pay on time when it is set aside as you earn. A Pryme Business Account keeps pounds separate from naira and other currencies, and the Finance agent can prepare a monthly tax provision for a director to approve.
Questions people ask
When do I need to register my company for Corporation Tax?
GOV.UK's company set-up guidance gives the window as within 3 months of starting to do business. You can also register at the same time as incorporating.
Do I register for Corporation Tax if my company has not traded?
A company that has not started to do business may be dormant for Corporation Tax. Check GOV.UK's dormant company guidance and tell HMRC.
Why does my first year need two tax returns?
A Corporation Tax period cannot exceed 12 months. If the first accounts cover longer, you file two returns, each with its own payment deadline.
When is Corporation Tax paid?
In GOV.UK's example, payment deadlines fall nine months and one day after each tax period ends.
Sources
- GOV.UK: Corporation Tax (updated 23 Oct 2026) · accessed Oct 2026
- GOV.UK: Set up a private limited company, register for Corporation Tax · accessed Oct 2026
- GOV.UK: Your limited company's first accounts and Company Tax Return (updated 22 Oct 2026) · accessed Oct 2026
- Companies House: Life of a company, part 1 accounts (updated 23 Oct 2026) · accessed Oct 2026
- Companies House: Life of a company, annual requirements (updated 30 Jun 2026) · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.