Report your lost or stolen passport to the local police as soon as possible. This reduces the risk of someone using your identity if they stole your passport or discover it where you misplaced it.
Schedule an appointment with the nearest U.S. Embassy or Consulate to obtain a replacement passport. The U.K. has two embassies - one in London, England, and one in Cardiff, Wales. Visit the the embassy's website to book your appointment online (see Resources).
Download and print a passport application form DS-11. Skip the first two instruction pages, as the U.S. Embassy in London website explains that these do not apply to applicants who are in the U.K. Complete the rest of the application and sign at the end.
Obtain proof of identity and proof of U.S. citizenship. Acceptable ID can be a valid driver's license, while the proof of citizenship must be a birth certificate or naturalization certificate, among other choices. You may need to contact a relative in the U.S. to fax these forms to your hotel, or call the National Center for Health Statistics, which can direct you to your state for a certified copy of your birth certificate.
Have a passport-sized photograph taken of yourself. The U.K. has photo booths for this purpose at many grocery markets, such as Sainsbury's, ASDA, Boots and Tesco. These booths are very inexpensive and only take a few minutes to print your photos.
Make sure you have the application fee ready for your appointment. You may pay in U.S. dollars or U.K. sterling, or use a credit card or International Money Order. Personal checks are not accepted.
Take your application and all supporting documents to the U.S. Embassy for your appointment. If you're in another U.K. city, visit Megabus website to book a cheap trip to London or Cardiff, which may cost as little as £1.50 (see Resources).
