Each divisional police station has a van for the accommodation of prisoners and transportation of officers. The Metropolitan Police Service makes extensive use of these, particularly among the Territorial Support Group, which has carries out public order duties and adapts the vans to carry riot protection equipment.
Police vans have a flip down wire shield across the windscreen, which helps prevent projectiles from damaging the vehicle. Most vans have the "Jam Sandwich" marking scheme within the Metropolitan Police District, while others use Battenburg markings, although as of 2008, the Metropolitan Police are transitioning from "Jam Sandwich" to Battenburg. Traffic Polices vans use the Battenburg marking scheme due to its high visibility factor. Some vans are fitted with special cameras to film speeding motorists and others are used for Automatic Number Plate Recognition. All police vans require a trained officer to drive them.
Modern police vans replaced the older Black Maria and the Morris Minor as these were usually crudely adapted for accommodation of a prisoner. Modern police vans have steel cages fixed into the bodywork.
The need for a secure police van was realised when prisoners who had been violently resisted arrest needed to be transported. The concern was aired that if transported in a normal Panda car, the prisoner might attack the officers or vehicle, causing the car to crash. One of the ideas suggested was cost effective and simple, which consisted of adapting vans with steel cages to separate the prisoners from the officers, creating a safe environment in which to transport prisoners.