Over 1,000 illegal migrants have been arrested following random spot checks on tube passengers and pedestrians in London, Home Office figures have revealed.

The joint exercises by the police and immigration service have become a regular weekday event in the capital.

In a Commons written answer published yesterday, Des Browne said: "While immigration officers do not have the same powers as the police to stop and search individuals in public places, they may legitimately question people to determine their immigration status where there is reasonable suspicion that a person is an immigration offender."