La Coda Dello Scorpione AKA The Case of the Scorpion's Tail
(1971, George Hilton, Anita Strindberg)
Opens in London, then shifts to Athens.
An ALDxxxB-registered London Transport AEC Routemaster on route 1 back to Catford:
Another, on route 53:
Strindberg is passed by another RM, then an AEC RT:

Nice view of a passing RT on route 172:
RM1641 (641DYE):
In Athens, several buses appear; only one is seen clearly from the front, and it appears to be a Scania-Vabis: