Upvote:1
From the official UK Government web site:
You donβt have to transfer your visa - you can carry both your old and new passports when travelling to or from the UK instead.
You can transfer your visa to your new passport if you wish, but this costs money. Because carrying both passports is free, you might not wish to spend the money.
Remember to inform your country's passport service that you need the old passport returned because it has valid visas in it.