British citizen or dual national travelling to the UK? You may not be able to rely on a foreign passport alone. If your UK passport is expired, very old, lost, damaged or never applied for, you risk problems at check-in or boarding. ASAP can help you get your UK passport fast from overseas.
Since 25 February 2026, British and Irish citizens cannot get a UK ETA, so you are expected to prove your citizenship with a valid British passport.
An emergency travel document is a single-journey measure with heavy restrictions. You must be travelling within six weeks, many countries limit or refuse it, and some destinations keep it on arrival. It gets you one trip. It does not get you a passport.
An eligible renewal gives you a full ten-year passport. It is valid for every trip, every visa application and every identity check, not just one journey.