This new spate of vehicle crime involves thieves over-riding the vehicle’s immobiliser and connecting a laptop into the on-board diagnostics (OBD) socket to disable the alarm and reprogram a new key.

Once the new key is cut, the thieves are able to return to the vehicle and unlock it and simply drive away. The crime is gaining more prevalence since EU rules came into force which must allow non-franchised dealers to be able to carry out repairs, because this has led to manufacturers making on-board diagnostics sockets more easily accessible.

An East London-based fleet is one of many to have fallen victim: asbestos removal specialist Silverdell has turned to aftermarket security devices to secure its van fleet after four Ford Transits were stolen and two more had their catalytic convertors removed.

To counter the problem, Silverdell has fitted coded boxes over the port. It has also had clamps fitted over its catalytic convertors to deter thieves who steal the units because they contain precious metals such as platinum.

Silverdell’s Wayne Farmer said: ‘We have installed a box to each of our vans which fits over the OBD plug and has a four-digit code to access it. The thieves cannot access the plug, or break into the box, therefore stopping further vans being stolen. A sticker is applied to the area where the OBD is located.’

Farmer added that the firm has fitted catalytic convertor clamps to each of its vans, involving one-metre of thick steel cable which goes through the chassis to secure the unit. He said that action was necessary because the high rate of catalyst thefts meant there was a backlog of replacement parts.

He added: ‘Due to the number of thefts in the UK, Ford has got a backlog of orders and main dealers are estimating delivery of 10-12 weeks, which means the van is out of use until replaced, and also means an increase in the cost of van rental.’