Follow this van

Apparently there is an arrangement between CTV ( Cash-in-transit van ) operators and local police forces that if a patrol car is not on assignment then it will tail a van that it comes across on its rounds. Hence the request.  Unfortunately this can lead to an escalating sequence of evasive and counter-evasive driving if the patrol car happens to be unmarked, as the van drivers try to escape from the suspicious vehicle on their tail...