Since you have no answers yet… I’m not British, but this may help.
If you are living in the USA you will need to change your name if you want to take the surname of your husband. Our surnames do not automatically change to that of our husband when we sign the marriage certificate. We can elect to legally keep the surname given to us at birth, even though we’re married.
My last name was legally still my maiden name until I went to the Social Security Administration Office and filed a name change with them. That required a certified copy of my marriage certificate, photo ID with my maiden name and the correct form to be filled out. (If you don’t have a US social security number this wouldn’t apply to you. But if you are a resident alien, I believe there will be other paperwork to file with the US fedral government.)
Next I went to DPS (known as “the DMV” in every other state I’ve ever lived in) with my current driver’s license and my marriage certificate. (I also brought the receipt from the SSA Office that showed I’d begun a name change there, but it wasn’t required.) I waited in line, paid my $11 and had a new photo taken. My license with my married name arrived in the mail a few weeks later.
To change my (US) passport I needed to fill out the correct form and mail my current passport and a copy of my certified wedding certificate to the passport office as proof of name change.
In every instance when I have needed to update my name, a CERTIFIED copy (one with the raised stamp, not just a photocopy) has been sufficent evidence of my legal right to claim that surname (without a court order). I’ve yet to hear of or see any agency requiring an alternate or additional document. (Although my employer did want proof that I had changed my name with the SSA, since my payroll taxes must be deducted under the same name that I have registered with the SSA.)
As far as changing a British passport, the British Embassy in Washington published this information on their website (http://ukinusa.fco.gov.uk/en/help-for-british-nationals/passports/what-passport/name-changes/):
Change of name on marriage or civil partnership
If you are married and wish to change your last name to your husband’s/wife/civil partner’s last name or want your passport to have the observation ‘the holder is also known as’ you must provide the following documents when you apply for your new passport:
- Your original marriage certificate/civil partnership certificate
- Your current/previous passport
Use of your maiden name
If you are a married woman and you wish to use your maiden name and you are known by this name for all purposes we can add an observation in your passport “The holder is the wife of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .” even if your passport is in your maiden name.
If you are a woman who is, or has been, married and you use both your husband’s name and your maiden name, but neither for all purposes, you will be granted a passport in the name you use most often, with an observation in your passport that you are also known as “……” (your lesser-used name). These changes can only be made when you renew your passport.