My UK passport is due to expire soon and I will renew it using the overseas service. However this requires me to send the old passport back to the UK, and I will be in the USA with no passport while this is being processed. Is there a temporary document I can apply for while waiting to receive the new passport? I have a valid UK driving licence, but I am worried that this may not be accepted as a form of identification, for example, if the police want to check documents
If you have the old passport number, you can print your electronic entry record here and show it along with your UK driving licence if stopped by the police or Border Patrol.
It could cause delays, but not necessarily, and in any case you'd be fine in the end.