What must a UK company include in its email signature?

Quick answer · the 30-second read

A UK limited company must include four things: its full registered name, where it is registered, its company number, and the address of its registered office. This comes from company law, not from etiquette. The rules apply to business letters, order forms and websites, and a business letter sent by email is still a business letter. Plenty of small companies have a signature with just a name and a job title, and are not complying.

KEY FACTS A UK company must show its full registered name, where it is registered, its company number and its registered office address on business letters, order forms and websites. The rules sit in section 82 of the Companies Act 2006 and the Company, Limited Liability Partnership and Business (Names and Trading Disclosures) Regulations 2015. A business letter sent by email counts. What the communication is decides the rules, not what format it arrives in. The registered name must appear on all business correspondence, which is a wider category than business letters. If you name one director in a business letter, other than in the text or as the person signing, you must name all of them. Everything must be readable by the naked eye, so very small or faint text can fail the requirement. Limited liability partnerships have equivalent duties. Failing to comply is a criminal offence, though enforcement is uncommon. A VAT number is not required by these rules. That comes from VAT law and applies to invoices.

What exactly do you have to include?

Four things, and they are all facts you can look up on Companies House.

Your full registered company name, spelled as it appears on the register. If the company is registered as Limited, use Limited rather than Ltd.
Where the company is registered, which will be England and Wales, Wales, Scotland or Northern Ireland.
The company registration number.
The address of the registered office. If you also show a trading address that is different, you have to show the registered office as well and make clear which one it is.

What it looks like in practice Jane Okafor Head of Operations jane@example.co.uk \| 020 7123 4567 Example Trading Limited, registered in England and Wales, company number 01234567. Registered office: 1 Example Street, London EC1A 1AA.

Where does this requirement come from?

Section 82 of the Companies Act 2006, and the regulations made under it, the Company, Limited Liability Partnership and Business (Names and Trading Disclosures) Regulations 2015.

Regulation 24 says the registered name must appear in the company’s communications. Regulation 25 sets out the further particulars that must appear on business letters, order forms and websites, which is where the registration details come from.

Anyone dealing with a company should be able to work out which legal entity they are dealing with, and find it on the register. That is harder than it sounds when a company trades under a different name from the one it is registered under.

Does this really apply to email?

Yes, where the email is doing the job a business letter would do.

The regulations do not mention email, which is why some people assume they do not apply. They are written around what a communication is rather than how it is sent. A letter is a letter whether it arrives on paper or in an inbox, and legal guidance consistently treats business emails this way.

There is a sensible limit. A one line reply arranging a meeting is not a business letter in any meaningful sense. But since signatures are applied automatically to everything, the practical answer for most companies is to set it up once and stop thinking about it.

What about naming directors?

There is a rule that catches people out. If a business letter includes the name of a director, other than in the body of the text or as the person signing it, then it must name every director of the company.

So a footer listing two of five directors is a problem. Most companies deal with this by naming none, which is why you rarely see director lists in email signatures.

The name of the person writing the email is fine. That is the signatory, not a listed director.

Does the text have to be a certain size?

It has to be readable by the naked eye. The regulations require displays and disclosures to be in characters that can be read without assistance.

This is worth a thought, because the usual instinct is to hide the legal details in very small, very pale text so they do not spoil the design. Taken far enough, that stops being compliance and starts being decoration.

Who else has to do this?

Limited liability partnerships have equivalent duties, adapted so that they disclose members rather than directors.

Sole traders and ordinary partnerships are not covered by the company rules, because there is no registered company. But if you trade under a name that is not simply your own name, separate business names rules apply, and you have to disclose your own name and an address where documents can be served.

What happens if you do not?

Failing to comply is a criminal offence under the regulations, and a fine is possible. Both the company and the officer responsible can be liable.

In practice enforcement is uncommon, and nobody is auditing email footers. The realistic consequences are more mundane. A client or supplier notices. It surfaces during due diligence when you are selling the business or raising money. Or you look less established than you are, which is the opposite of what a signature is meant to achieve.