Luxury cars face being hacked by criminal gangs to steal information, extort money from drivers or even cause vehicles to crash, experts have warned.
Cars fitted with wireless networks and internet connections can be exploited by hackers to access and control a car's systems, including braking and acceleration, according to security consultants.
Edmund King, president of the AA, told the Times: "You are now getting the connected car. You're getting cars that are connected to the internet 24 hours a day. If cybercriminals targeted automobiles like they're targeting other things we'd be in for a hard and fast ride.
"The more cars rely on technology, particularly remote technology, the more there is to get at."
The most dangerous possibility was criminals hacking into a car's safety systems, including cruise control and braking.
"Ultimately there could be a terrorist-type threat to transport systems," King said. "I don't think we're there yet but it's something that needs to be addressed."
In recent years, there have been thefts of Range Rovers and BMWs as thieves use a handheld device to bypass security systems on vehicles fitted with "keyless" ignition systems.
Researchers have discovered that it's possible to access a car's internal computer system, known as the Controller Area Network (CAN), through a car radio, Bluetooth or wireless network.
Jacques Louw, senior security consultant at MWR Security, said that hackers could turn on microphones in the car to hear conversations by occupants.
Experts warn that it would be possible to interfere with a car's speed and braking. Criminals could blackmail car owners to hand over money or make a Bitcoin transfer – or threaten to crash their vehicle while driving.
In a study published last year, hackers using a laptop were able to connect to a car's CAN in order to accelerate, break and switch headlights on and off as well as make the vehicle swerve.
According to Louw, dashboard entertainment systems are the easiest to hack into. "These things connect up to the internet, so you could launch any of the attacks that you do against a mobile phone."
Areas that are vulnerable include "core engine controls – the airbag controllers [and] the break controllers."
Many vehicles have sensors and computers recording a car's performance including braking, acceleration, speeding and cornering technique.
However, future technology could also be used for increasing road safety. King said next generation car systems will include a "Co-operative Intelligent Transport System" where cars will be able to communicate with each other, helping to prevent traffic accidents.