(Channel 4 satirical comedy series)

Episode 2.08: The Bullshitters:
Parody of The Professionals, with Keith Allan and Peter Richardson as Bonehead and Foyle.
Set and filmed in London, and AEC Routemasters feature:

Glimpsed at Trafalgar Square is an MD-class Scania Metropolitan:

More interesting are scenes of the duo jumping on and off Routemasters in service, in their underpants.
RM650 (WLT650) on route 77:

Unclear, also on 77:

RM1006 (6CLT):

RM1767 (767DYE) on 77A:

RM450 (WLT450):

Also this Ford Transit, and trousers: