Thames News - The New London Bus (undated)

Published on the Thames News Youtube channel, this is a compilation of clips from British Movietone News, opening with footage of horse buses:
….followed by a Daimler being started up:

London General AEC B B340 leads a convoy of preserved buses, which includes S742 and K424:

The prototype AEC Routemaster RM1 is seen on display at the Commercial Motor Show:

A Bedford C4Z1 of London County Council, YXW588:

We then see a number of Routemasters in service - RM562 (WLT562), RM457 (WLT457), RM568 (WLT568), RM555 (WLT555), RM491 (WLT491), and then RM568 and RM491 together, also RM549:
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Lastly a Leyland RTL creeps in, RTL1570 (OLD789):
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