Revenue inspector Scott is on the lookout for fare evaders attempting to force their way through the ticket barriers. Alex and Baba join forces with the police in a sting operation along a busy stretch on one of the city's busiest bus routes.
Revenue inspectors Karen and Peter stop dishonest commuters exploiting a transport loophole.
A prolific barrier-blagger is handed an eye-watering bill for three years of illegal travel, while in east London, tube enforcement officers Karen and Peter stop passengers cheating with discounted tickets.