Ray Taylor took the drastic action to fit his Citroen Dispatch with a system that will send out a 120-decibel siren – the equivalent of a jumbo jet taking off. If that fails to scare criminals, then a shock from the door handle should work.

The Wolverhampton workman has lost more than £5,000 worth of equipment in two years.

He told The Sun: “It’s solved all my problems, so I can sleep easy. The shock isn’t going to do any lasting damage but it will make you jump a bit.”

Ray has copyrighted his design and is now charging £380 to fit similar systems. He was told by police his invention is completely legal as long as he puts a clear warning sign on the vehicle that volts are running through the van.

The device sees a 1,000-volt zapper from a fly swatter fitted to a metal plate in the rear door handle. The siren and a strobe light are also on the same circuit, which is fitted to a switch in the cabin. Once someone tries to pull on the handle, the switch is activated through sensors attached to the van’s door. The shock is isolated to the handle and the rest of the van is not live. Underneath the handle is the warning, reading: ‘Danger Live Terminals.’

West Midlands Police have said the action is completely legal as long as the sign is visible, though they would not endorse using such methods of deterrent.