(1967, Sidney Poitier)

School drama: temporary school teacher Poitier boards a London Country Area AEC RT on route 457 as the opening credits roll - unclear registration but this could be RT611 (HLX428)

Leaving Wapping Tube Station he boards (former) London Transport Leyland Titan PD2 RTL1050 (LLU829) on route 15:

The journey is intercut with a brief shot of Routemasters, one of which is RM1720 (720DYE) on route 18:

There is a scene which is probably aboard RTL1050 before arrival outside school:

There is a poster on the rear window for 'Henlys':

As the movie progresses a school trip is organised, and RTL1050 is hired (note the school bus sign in the rear window), but it's an RT that brings the party back, RT2107 (LYF83), although one wonders if there was an attempt at continuity by using the same advert on the back of the bus (RT2107 was at the time owned by Margo's Coaches):

There's a brief interior scene, and the sign in the rear window has reappeared but in a different position. If the previous interior was of RTL1050, then so is this:

Seen next is an RTL on route 15 with fake registration LLP629 - close examination shows it's actually RTL1050 again, but why change the registration plate?

Next is an RTL on route 23 with fake registration BXC51, which would have been more appropriate to a 1930s STL than an RTL. It seems likely this is again RTL1050, although I can't prove it!

It appears this also happened in Hot Millions, made in 1968, where there is some evidence RTL1050 carried registration LLU992.