What should dual Thai/British nationals know about renewing a British passport?

If you hold dual Thai and British nationality, be aware that the UK passport office now requires a copy of all passports you hold when renewing your British passport. It is crucial that the name on both your British and Thai passports match exactly, including middle names, as discrepancies can lead to complications and delays in the renewal process. Other users have shared similar experiences, emphasizing the importance of consistent name spelling across all documents. If you are in Thailand, you can inquire about renewing your British passport at the British embassy.