Mobile traffic policemen on motorbikes are introduced to London.
Full title reads: "London. 'Speed merchants' - beware!' First of mobile police traffic control are now on duty."
Three police motorcyclists ride out of entrance. They dismount their motorbikes and stand by them. The bikes and men are inspected by two bowler hatted men. The policemen are then inspected by another man. The policemen point out various points of interest on their uniforms and bikes.
One of the traffic cops rides his motorcycle into picture, gets off and pretends to direct traffic.