My 15 year old daughter has a UK and a Thai passport but the Thai one has run out. I cannot renew until her mother returns from overseas in December. Previously she's always left Thailand on the Thai one but now she needs to leave on the UK one which is 2 years old and has no stamps in it. Has anyone any experience of this, will there be a problem at immigration?

She won't be able to as she didn't enter Thailand on it. The mother should go to a Thai embassy wherever she is and organise a document which can be signed and witnessed there and sent to Thailand gving her permission for the passport application.

Thanks for that Samran, may I ask how you know this as I'm getting conflicting answers. Also the UK passport was issued in Thailand, surely if someone has a passport issued in Bangkok they would have to use it to go out if they were Thai but without a Thai passport.

Computer matching has been happening for a while. Other reports here on Thai visa of children entering on one passport and trying to depart on another (generally the Thai pp) and being prevented from leaving.

Also if leaving on a Brit passport there would need to be a entry stamp in the old Brit passport.

Best to consider Thai immigration as a accounting statement. Debits must equal credits.

And yes, I am a Thai dual citizen.