Border Force is responsible, on behalf of the Home Office, for passport control checks at all UK airports. Key performance indicators are established for maximum queuing times at UK immigration.
As part of our overall passenger service monitoring programme, Heathrow records queue lengths and produces information on a monthly basis.
In each of Heathrow's terminals, immigration queues are measured by an independent team.
Every 15 minutes the last passenger in the queue is identified and timed until they have cleared the immigration process. This takes place across all Heathrow terminals, every day, between 05:00 and 22:00.