“I [old name] of [your address] have given up my name [old name] and have adopted for all purposes the name [new name].
“Where applicable, I have informed the police that I have given up my name [old name] and have adopted the name [new name] and understand that a failure to do so is a criminal offence.
“I also understand that when I apply for official documents in my new name, such as a British Passport, the relevant authorities may check the history and validity of my old name [old name] and new name [new name]. They may also check the information in any other supporting documents they have requested.
“Signed as a deed on [date] as [old name] and [new name] in the presence of [witness 1 name] of [witness 1 address], and [witness 2 name] of [witness 2 address].
From https://www.gov.uk/change-name-deed-poll/make-an-adult-deed-poll