Crafty burglars stealing car keys from houses in order to grab targeted cars are becoming rife, according to stolen vehicle recovery specialist Tracker.

The firm's managing director, Kevin Watters, said Tracker's stolen vehicle recovery system had logged 151 thefts of cars with keys since January, compared with a total of 560 over the past eight years.

Of the 151 cases, 65 sets of keys were stolen from the car owner's house during a burglary and 35 were taken from the driver by force.

Watters said the rise was due to the increased use of immobilisers.

"Every car comes with one and they've got better and better but, if a thief has the keys, he's away to the races," he said.

"We've been doing this for eight years and in the first three or four, I don't remember a theft where the thief burgled the house to get the keys."

Over the past month, Tracker recovered 25 cars stolen with their keys, nine of which involved the theft of the keys in a burglary and six that involved the theft of the keys with violence.

This included the recovery of a BMW Z3, which Tracker retrieved in 30 minutes, after its keys had been stolen in a burglary.

Watters said thieves were using some ingenious methods to obtain keys to cars they had targeted.

"People are being carjacked," he said. "You're driving along, your car is bumped from behind. You stop and get out and so do they. Then they jump in your car and drive off."

Other cars were stolen at knife and gunpoint and one car owner was clubbed over the head during a house burglary to obtain the keys.