How old do you have to be to change your name in the United Kingdom?

According to the Citizens Advice Bureau, a person must be over 16 years of age for a legal name change in the United Kingdom. The new name may be used immediately without completing any forms or paperwork and can be used for official purposes, such as travel documents.

A person can change either his first or last name and may add or drop names at any time, according to the Citizens Advice Bureau. It should be noted that some organizations require written proof of the name change, so it may be beneficial to carry written proof signed by a doctor or priest.