Sex magazine cover girls are being murdered. Baffled police send one of their number into the porn industry undercover. Nasty as it sounds, but London street scenes include some interest. Seen through a police car window are a London Transport DMS class Daimler Fleetine followed by an AEC Routemaster, also a Bristol RELH in National Bus Company white livery:

Seen from above are two more DMSs and a Routemaster, while a London Country Green Line RP class AEC Reliance/Park Royal passes in the foreground: