Security systems built into luxury vehicles have become so sophisticated that thieves are increasingly taking cars at gun point.

Police are warning drivers of increases in violent “car-jackings”, as gangs cruise the streets looking for vehicles to match orders they have taken.

Luxury vehicles worth £1m have been stolen from Essex in just a few weeks – with BMWs, Mercedes, Porsches and Jaguars being the main targets.

The RAC and the AA said the car-jackings were a response to new anti-theft devices, such as immobilisers and alarms, that are being fitted to luxury cars.

In the past three years, figures for car crime have dropped, but violent attacks on drivers have increased.

Motorists have been attacked at traffic lights, in petrol stations and on their own property.

A 54-year-old woman from Birmingham had her BMW 323i stolen after she was attacked with an iron bar.

In the West Midlands, a 72-year-old man died from the head injuries he received when his car was taken from him.

Blackspots for this type of crime are Manchester, Bristol and Birmingham.

Detective chief constable Graham Moore, of Essex Police, who has been investigating thefts by gangs, points out that there have been about 20 attacks over the past eight weeks.

The gang being investigated, mainly thieves in their twenties, sell cars valued at between £35,000 and £45,000 for less than £1,000.

But car-jacking still only accounts for a tiny proportion of vehicle crime – in the worst affected area, Greater Manchester, it is just 1%.

A Direct Line spokesman said there was a trend for more high-performance cars being stolen but the numbers are still very low.

“We have had about ten reported cases in six months in the south east region,” he said.

A recent Direct Line survey shows that more drivers are taking precautions while driving, with two thirds saying they sometimes lock their car doors for extra security.

Vehicle recovery system Tracker, helped to recover luxury vehicles worth £609,000 in March.

According to the RAC Trackstar, a provider of Global Satellite Monitoring, one way to crack car crime is to install a tracking system into the vehicle itself.

Figures show that 90% of vehicles fitted with one of the four major tracking devices were recovered last year, compared to only a fraction of those without.