Can I travel on my old passport while waiting for a new one from the British Embassy in Bangkok?

When applying for a new passport at the British Embassy in Bangkok, users can retain their old passport; however, it is generally stated by the embassy that the old passport cannot be used for international travel. Some users have shared personal experiences suggesting that they were able to travel with a corner-cut old passport, but caution is advised, especially regarding strict immigration controls in places like Singapore. Emergency travel documents are an option but can be costly and involve additional trips to the embassy.