You can renew your passport by mailing the forms to the UK, no problem there. A passport is a passport, it doesn't matter which authority you go through as long as it's an official UK one. The problem is if you go through th UKPA, they won't mail outside the UK. Yiuou can have it sent to anyone and they can mail it on, but I would worry about losing it.

Is it legal to send passports via any carrier to other countries? Best get that checked out before applying. Years ago I posted a passport via the mail and it was returned.

http://www.direct.gov.uk/en/TravelAn...port/DG_174096

If you have someone in the UK then you could just have it mailed to them and they could then mail it on to you.

not saying you should, just that you could.

Most of the passports issued in the UK now require biometrics and you get the RFID chip in the back. That requires an appointment, which you wouldn't be able to make without a valid passport.

Getting the passport reissued in the US via the Embassy is still cheaper than paying for a flight home to get it done in the UK.