The British Embassy has confirmed to me that my Thai wife just needs to bring her old expired passport which contains a valid unexpired UK visa along of course with a current passport to enter into the UK. However I won't entirely trust what I have been told until evidence from other people's experience to confirm this. The last thing I want is to arrive at Heathrow Airport and my wife being denied entry because of no visa in her new passport.

Appreciate anyone's comments on their own experience of a Thai wife/girlfriend/partner entering the UK with a valid unexpired UK visa but in an old passport.

Absolutely RHCP.

Wife does it all the time.

New passport has no documentation, so just shows both passports whenever required.

Including change of name stamp that no one can ever find until she shows them herself.

No problem, hope all goes well with travels.

Good luck

Moss

She will need to show both passports at airline check-in in Bangkok too as they will need to see the visa before allowing her to fly, but no problem