Business surface intelligence for UK companies

Must a UK company show its company number on its website?

Yes. A company registered in the United Kingdom must show its registered number on its websites, together with its registered name, the part of the UK in which it is registered and the address of its registered office. The rule is regulation 25 of the Company, Limited Liability Partnership and Business (Names and Trading Disclosures) Regulations 2015, made under section 82 of the Companies Act 2006. It applies to every company that has a website, and to LLPs.

Key facts

• The registered name must appear on every company website (regulation 24(2)).
• On websites, business letters and order forms a company must also show where it is registered, its registered number and its registered office address (regulation 25(1) and (2)).
• "Its websites" includes any part of a website the company has caused or authorised to appear, so a page about the company on someone else's site counts (regulation 29(d)).
• The information must be readable with the naked eye (regulation 20): no light grey on white, no image-only text.
• A company number is eight characters. Leading zeros are part of it.
• Failing to comply without reasonable excuse is an offence by the company and every officer in default, with a fine of up to level 3 on the standard scale, currently £1,000, and up to £100 a day while it continues (regulation 28).

What exactly has to appear

A company's registered number is the number Companies House gave it on incorporation. It never changes, even when the name does, which is exactly why it is the item that identifies you.

Where on the site it has to go

The regulations do not name a page. They require the particulars "on its websites" and, through regulation 20, in characters that can be read unaided. Companies House's guidance says only that the information must be displayed on the website. In practice a one-line legal footer on every page is the standard answer, because it is always present, it is where people look, and it meets the separate E-Commerce Regulations requirement that this information be "easily, directly and permanently accessible". A legal line that exists only on a page nobody can find is a weak answer to both rules.

How to write the number

• Use all eight characters. A company number is a string, not a quantity: 01234567 is not 1234567. Many sites print seven digits because a spreadsheet or a designer stripped the leading zero. That is the commonest error we see, and it is enough to make a number fail to match the register.
• Companies registered in Scotland and Northern Ireland have two-letter prefixes (SC, NI); LLPs have OC, SO or NC. Keep the prefix.
• Label it so a reader cannot mistake it: "Registered in England and Wales, company number 01234567". "Reg. no." is understood but is also used for VAT and other registrations; say which.
• Keep it as text, not an image, so that people and software can read it.

What happens if it is missing

Three things, in increasing order of likelihood.

1. A criminal offence. Regulation 28 makes non-compliance without reasonable excuse an offence by the company and by every officer in default, punishable by a fine of up to level 3 on the standard scale (£1,000) and a daily default fine of up to one-tenth of that for continued contravention. Prosecutions for a missing website footer are rare.
2. Trouble enforcing a contract. Under section 83 of the Companies Act 2006, if a company in breach of the disclosure regulations sues to enforce a contract, the other side can have the claim dismissed by showing it has a counterclaim it could not pursue, or suffered a financial loss, because of the breach, unless the court finds it just and equitable to let the claim continue.
3. Nobody can confirm who you are. This is the everyday cost. Customers, suppliers, banks and verification services check a website against the register. A site with no number, or a number that does not match, looks like a site nobody stands behind, and increasingly gets treated that way.

Rules you will meet at the same time

• The E-Commerce Regulations 2002, regulation 6. Almost any business website that offers goods or services, sells online or carries advertising is an "information society service", and must make available the provider's name, geographic address, contact details including an email address, the register it is on and its registration number, and its VAT number if the activity is subject to VAT. For a company, the registration number is the company number, so the two rules point at the same line of text.
• VAT. If you are VAT registered, the E-Commerce Regulations require the VAT number on the site and the VAT Regulations require it on VAT invoices.
• Regulated firms. FCA-authorised firms have their own status-disclosure rules, and appointed representatives must name their principal. Those sit beside the company-law rules, not instead of them.

How Observes reads this

A company number on a company's own website is the one disclosure that ties a site to a single legal entity without any inference: there is one company with that number, and the site says so about itself. It is the strongest kind of evidence in the scale Observes uses, which is why we call that class PROVEN. A registered name with the registered postcode on the same page is the next strongest. A name on its own is not evidence that a site is yours, because names are not unique and are not always on the register exactly as written. If you want to be verifiable, the number, all eight characters, is the thing to get right. How the classes work is on the method page.

This page is general information about UK company law, not legal advice. The regulations were checked on the date shown below; check legislation.gov.uk for changes after that.

Written by Nathan. Last reviewed 8 October 2026.