Mr Tom (John Thaw) looks after a boy evacuee from London in his Norfolk home during the Second World War. He and the boy return to London at separate times on a Great Western Railway train (thanks Terry Browne). On arrival they both jump on an early postwar AEC RT. (thanks John Newton and Alan Sinclair)
Leon Daniels confirms the RT seen in this movie as RT190 (HLW177) "which is restored to as new condition and so has restricted blinds, plain headlamps, etc."