Something in the City (1950, Richard Hearne)

The opening credits have shots of Central London, featuring RT2289 (KGU318) and RT1608 (KLB730) seen close to Trafalgar Square and followed by an unidentifiable STL:
Many RTs and STLs are seen:
Hearne jumps precariously onto an STD class Leyland Titan driving at speed down the Strand:
As he's seen boarding a back projected RT is seen behind:
When he switches to a tiny motorcycle, he's pursued by RTL625 (KGU75):
The couple in this late scene are followed in back projection by two different RTs:
(thanks Colin Read)