Companies House guidance sets out the main requirements for incorporating a company in the UK. The guidance entitled Incorporation and Names also provides advice on checking which names are acceptable to Companies House when naming a company.Choosing a company name can be one of the most important considerations for a new business. The name must meet certain legal requirements and at the same time be an effective marketing tool. One of the first steps after choosing a name is to check that it is actually available. Companies House offers a free WebCheck service which allows users to search 170 million digital records including company names for free. It is also important to check the Trade Marks Register to ensure that the proposed name does not infringe an existing trade mark.There are also a number of restrictions set out in legislation. These restrictions include:The name of a private company limited by shares or guarantee must end with ‘limited’ or ‘Ltd’.The name of a public company must end with ‘public limited company’ or ‘p.l.c.’.Certain expressions and abbreviations which describe a particular form of company can only be used at the end of a name, such as ‘Limited Liability Partnership’ or ‘Community Interest Company’.A name that could suggest a connection with the UK government, a devolved administration, a local authority or a specified public authority.A name that includes sensitive words or expressions included in regulations. A name that includes words that would constitute an offence. An offensive name. A name which is the ‘same as’ an existing name on the index. The use of certain characters, signs, symbols and punctuation in a company name.There are also limits for some sensitive words or expressions. For example, a word or expression that may cause criminal offence. This includes names that could be taken to cause criminal offence.Planning note:The above considerations apply to the registration of a new company. Existing companies may also want to use a trading name, and most of the above comments would also apply to its selection. However, there is no formal registrar of trading names and other options need to be considered. For example, it may be advisable to register a new company with the required trading name as its company name, in this way poaching of the name by competitors can be restricted. The new company does not have to trade, it is just a device to secure the name. And, as mentioned above, a search of the Trade Marks register may be prudent.