For a Thai national, what is the procedure for travelling on a Thai passport in her married name while using an old (pre-2012) ILR stamp or vignette in an old passport in her maiden name? How will airline check-in staff and British immigration officers be persuaded that the passports refer to the same person? A Thai immigration officer would see that the national ID numbers were the same and note that only the names were discrepant.

I'm asking for a friend, but I do know that the option of getting a biometric residence permit is unacceptable.

What exactly are you asking?I

If the woman has a valid Thai passport it can be used for travel and entry into Thailand

If the lady has a valid UK passport that can also be used.

The lady could exit the UK using a UK passport and enter Thailand using her Thai passport and visa versa.

Thai (and British) women are permitted to use their maiden name if they so choose.

What exactly are you asking?I

If the woman has a valid Thai passport it can be used for travel and entry into Thailand

I'm asking how she can use her Thai passports to enter the UK. If the passports were in the same name, we know she could just present both, though many carry the intermediate passports to be on the safe side.

Present both passports and the marriage certificate, with a certified translation if that is not in English, as evidence of the name change.

She can take her new passport to the Thai passport office where they will place a stamp in it detailing the old passport number and her previous name.

Thanks, Apetley. That should reassure my friend. My wife got a similar stamp when she extended her first passport and changed to her married name.

Thanks, Apetley. That should reassure my friend. My wife got a similar stamp when she extended her first passport and changed to her married name.

How are passports "extended" ?

Passports can be extended by adding an official stamp saying the validity has been extended. In this case, a 5-year passport was converted to a 10-year passport. You may be aware that expatriates' British passports were being slightly extended in the passport crisis of Summer 2014. It's an old trick.