If you have changed your name via deed poll, you may need to update your passport. This means cancelling your old passport and applying for a new one. It is important to make sure that your passport reflects any changes you have made to your name. You should also make sure that your name on the passport matches the name on all travel tickets.
Additionally, other institutions may require your passport as an evidence for your name change. The Passport Office requires documentary evidence to confirm the link between your former name and your new name.
In some circumstances, a deed poll is sufficient, such as:
Change of name by a deed poll
UK law allows people to change any or all of their names by a deed poll, provided it is not done for fraudulent purposes.
Separation
If you wish to return to the name you used before your marriage or civil partnership, however divorce or dissolution has not taken place yet, you will need to change your name by deed poll first and then apply for a new passport.
First passport in different name to birth certificate
If you are applying for your first passport under the name by which you are known, but the name is different to the one on your birth certificate, then you can use a deed poll as evidence of your name.
All you need to do is complete the document with the name on your birth certificate down as your current name, and the name you are known by as your new name. This will provide evidence that the name you are known by is your new legal name. The document will then be sufficient evidence to support a passport application in that name.
https://www.netlawman.co.uk/ia/changing-name-passport
https://www.ukdp.co.uk/name-change-passport/
https://deedpolloffice.com/change-name/frequently-asked-questions#do-I-have-to-update-my-passport