Half of the new cars launched this year have been given a poor security rating after investigators found their keyless entry systems could easily be bypassed by thieves, who use relay equipment to hijack the car’s entry code from the victim’s home.

Thatcham Research, which tests cars on behalf of car insurers, said the 2019 models of Ford Mondeo, Hyundai Nexo, Kia ProCeed, Lexus UX, Porsche Macan and Toyota Corolla had all been rated as poor because they were vulnerable to this type of theft.

In recent years, car thieves have used specialist scanners to relay the car’s security entry code from the key fob, often from inside the owner’s home. Following a spate of thefts, owners have even resorted to putting their keyless entry fobs in their fridge at night.

Thatcham’s new security ratings specifically address the problem for the first time. The body said the Audi e-tron, Jaguar XE, Land Rover Evoque and Mercedes B Class 2019 models were all equipped to resist the relay attack technique, and had been rated as superior.

Richard Billyeald, the chief technical officer at Thatcham Research, said most of the cars rated as poor would have been rated good had they not been susceptible to attacks.

“We’ve seen too many examples of cars being stolen from driveways in seconds. Now, any vehicle that is assessed as having a vulnerable keyless entry system will automatically not achieve the best rating. Security has come a long way from the early 1990s, but the layers of security added over the years count for nothing when they can be circumvented instantly by criminals using digital devices.”

He said storing all keys, spares included, away from household entry points was important, as it hampers the criminal’s ability to relay the signal. He also suggested that owners consider turning off the keyless entry system entirely.

Home Office statistics showed there were 110,000 vehicle thefts in 2017/18 – up 10% on the year before and the highest level for a decade. When the German General Automobile Club (ADAC) tested 237 keyless cars, they found only seven were not susceptible to being both unlocked and started.

The Association of British Insurers said its members paid out a record £376m for car thefts in 2018, up 27% on the year before. In January, the consumer group Which? warned that most of the UK’s keyless cars were at risk of theft.

Laurenz Gerger, the policy adviser for ABI, advised the owners of vulnerable cars to consider using a signal-blocking pouch. “Car thieves have been having a field day lately, partly driven by the vulnerability of some cars to keyless relay theft. Crime stats show vehicle thefts are at their highest level for a decade.”