Can I have some advice regarding my nephew please? He is 7 weeks old, a dual UK/Thai national. He is currently in Thailand but is due to move to the UK soon when his mother's visa is approved. At the moment he only has a British passport. Can he leave Thailand using his British passport or will they need to apply for a Thai passport before they can come to the U.K?
TLDR : Answer Summary
A dual UK/Thai national infant can leave Thailand using only his British passport, as confirmed by past experiences. Immigration authorities should accept this and may make a note about his lack of an entry stamp due to his recent birth. However, it's advisable for the parents to consider applying for a Thai passport as well, especially if they intend to return to Thailand in the future. Obtaining a Thai passport can facilitate travel and avoid potential issues regarding his dual nationality.