Company name rules: what Companies House will not register

Companies House will not register a company name that is the same as an existing name, is offensive, uses a sensitive word without permission, contains computer code, or suggests a false link with a government or international body. The rules come from the Companies Act 2006, as tightened by the Economic Crime and Corporate Transparency Act 2023 (ECCTA). Companies House’s Incorporation and names guidance, last updated 19 October 2026, sets them out.

What must a company name include?

A private limited company name must end with “Limited” or “Ltd”. A company registered in Wales can use “cyfyngedig” or “cyf” instead.

Only company-type expressions, such as “community interest company” or “CIC”, can appear at the end. Some private companies limited by guarantee can be exempt from using “limited”. See company limited by guarantee for the conditions.

What names will Companies House reject?

Companies House rejects a name outright if it falls into one of these categories:

• The same as an existing name on the index
• Offensive words or expressions
• Words that are an offence to use
• Sensitive words used without approval
• Computer code, in whole or in part
• A false impression of a link with a foreign government, its agencies, or an international body such as the UN or NATO
• Names intended to facilitate crime, in the Secretary of State’s opinion
• Banned characters, signs, symbols or punctuation

The last three grounds were added or strengthened by ECCTA. Proposed names with a sensitive word are stopped automatically and reviewed by staff.

How does the “same as” test work?

A name is the “same as” another if it is so similar that the public is likely to confuse the two companies. Companies House ignores some details when comparing names.

• Endings such as “Limited” and “Ltd” are disregarded.
• Accented letters count as plain letters, so Ä is treated as A.
• Some words count as symbols, so “and” is treated as ”&”.
• Certain punctuation, brackets and blank spaces are disregarded.
• Only the first 60 characters are compared.

So “Smith & Jones Ltd” and “Smith and Jones Limited” count as the same name. There are exceptions for companies in the same group, or where the existing company consents.

What is a “too like” name?

A “too like” name is one that is registered but looks and sounds like an existing name, differing by only a few characters. The other company can object to Companies House.

If the objection succeeds, the Secretary of State must order the change within 12 months of the name being registered. Companies House allows at least 28 days to make the change. Complaints about trade marks, passing off or similar activities are not considered under this route.

Which words need permission?

Sensitive words need approval before you can register them. For most, you must get a letter or email of non-objection from the relevant body and send it with your application on form IN01. Annex A lists them.

Using a sensitive word in a business name without approval is an offence.

Can Companies House force a name change later?

Yes. Under ECCTA, the Secretary of State can direct a company already on the register to change a name that breaks the new rules. The ECCTA company names factsheet explains the sanctions:

• If the company does not comply within 28 days, the registrar can replace the name with the company number.
• Failing to respond to a direction can lead to a fine of up to £1,000.
• Trading under a name that has been directed to change, or replaced, can lead to a further fine of up to £1,000.

What if someone registers your name to block you?

You can complain to the Company Names Tribunal, part of the Intellectual Property Office. It deals with names registered mainly to stop someone else using them, or to demand payment to release them. If it upholds the complaint, it can order a change, and can direct Companies House to replace the name with the company number. Contact the tribunal on 01633 811035.

How to check a name before you register

Follow these steps before you file:

1. Search the Companies House name availability checker.
2. Search the register for similar names; see how to look up a company.
3. Check Annex A, B and C for sensitive words, and get any non-objection letter first.
4. Search the Intellectual Property Office trade marks register, since Companies House does not check trade marks.

What to do now

• If you are setting up, follow our guide to setting up a limited company.
• If you want to rename, see how to change a company name. It costs £20 online or £30 on paper, with an £85 same-day option; see Companies House fees.
• If you receive a direction to change your name, act within the 28 days to avoid the fines.

Frequently asked questions

Can two companies have the same name?

No. Companies House will not register a name that is the same as one on its index, ignoring endings like Ltd and comparing the first 60 characters.

Do I have to use Limited in my company name?

Yes, for a private limited company. It must end with Limited or Ltd, or cyfyngedig or cyf in Wales, unless an exemption for some guarantee companies applies.

What is a sensitive word in a company name?

It is a word, such as Bank, Royal or Chartered, that needs approval before use. Most need a non-objection letter from a named body sent with the IN01.

Can Companies House make me change my company name?

Yes. It can order a change for a “too like” name within 12 months, and under ECCTA it can direct an existing company to change a name that breaks the new rules.

Does registering a company name protect it as a trade mark?

No. Companies House does not check trade marks, so search the Intellectual Property Office register separately.