Updating your passport is typically one of the first priorities after a name change. It is your primary proof of identity and the document most frequently required for international travel and age verification. HM Passport Office (HMPO) has a clear process for name change applications, and a deed poll is the document they will ask for.
A passport name change is processed as a renewal application, not a new passport. You apply online or by post using the standard passport application process, selecting "change of name" as the reason. You will need to send your current passport (which will be cancelled and returned to you with holes punched through it) along with a certified copy of your deed poll. You do not need to send the original signed deed poll. A certified copy (a photocopy on which you have written "I certify this to be a true copy of the original deed poll", signed and dated) is sufficient.
Standard passport applications currently take up to ten weeks to process. A fast-track service is available through HMPO at an additional cost, which can reduce the processing time to approximately one week for a premium service. During the application period, your passport is held by HMPO and you cannot travel internationally, so plan the timing carefully if you have any upcoming trips.
There are a few additional considerations depending on your circumstances. If you are also requesting a gender marker change at the same time as a name change, HMPO requires additional supporting documentation, typically a letter from a clinician. If you are changing your name following marriage and using a marriage certificate rather than a deed poll, the process is similar but you submit the marriage certificate instead. If your name has multiple components (hyphenated surname, unusual characters), check HMPO's guidance, as UK passports are issued in uppercase Roman script.
Once your new passport arrives in your new name, it's one of the most useful to update early; you can use it as photo ID at banks, post offices, and most other organisations while you work through the rest of your records.