Left the UK yesterday (December 10th) for Thailand with my wife (Thai) and 2 kids (Thai/UK passports), 3 days before we left I realised my daughters Thai & UK passports had both expired ( UK 10 months previous & Thai 1 month previous), yes I know I'm an idiot, we checked in at Edinburgh (flying with Qatar) with her Thai passport and explained that she is going home to Thailand to renew her Thai passport "No problem on you go sir". Arrived in Bangkok today and logged onto British embassy site, 4 weeks to renew her passport or we can get an emergency travel document, but my question is, can she be refused entry to the UK with her expired passport if we don't get the travel document?

Deleted miss read the op.

Your daughter's Thai passport needs to be renewed so she can leave Thailand. (I presume birth certificates serve as entry stamps for foreigners born in Thailand.)

The expired British passport should be good enough for boarding the return flight as well as entry to the UK. While a British passport is supposed to be necessary for a Briton to enter the UK on the basis of being a British citizen, an expired British passport may be used and it is not clear what actually happens if other proofs of Britishness are offered. Traditionally, common sense is applied.

Thanks Richard, yes my daughters Thai passport will be renewed asap, we brought her Thai BC but were not asked for it at immigration, we also have her UK BC with us for the journey back to the UK.