Thieves are increasingly looking to steal catalytic converters from cars, according to yesinsurance.co.uk.
The converters, located on the underside of cars, are part of the exhaust system and remove harmful toxins from the vehicle's emissions. Once they are stolen, they are either sold on to garages as a whole unit or broken up for scrap.
"Catalytic converters are attractive to criminals because they are expensive, easy to access and contain rare metals such as platinum, which have been rocketing in price recently," said Paul Purdy of the online insurance firm. "It's not unusual for a new converter to cost in the region of £1,000."
Four-by-fours are a particular target because most have enough room underneath to get to the exhaust system without having to jack up the vehicle. Thefts usually happen overnight, the insurer explained, so drivers tend to find out what has happened in the morning when they go to start their vehicle.
"While car radios can be a popular target for criminals, catalytic converters now appear to be offering greater returns due to the high value and the fact they are easily accessed," Mr Purdy added.
Where possible, the insurer advises drivers to park in private garages. But if they have to keep their cars on the street, it should be in a well-lit area.