Callous criminals have used Facebook Marketplace to target unsuspecting victims. One car seller had a knife pulled on him during a 'test drive' before the vehicle was stolen and taken on a 10-mile joyride. Another conman tricked Rolex owners into handing over the expensive watches, while a masked gang travelled more than 60 miles to steal a bike they'd seen advertised on the site.

Buyers were also fooled by a fraudster flogging dangerous and unroadworthy cars with false documents. A full round-up of cases can be found below. Facebook has urged Marketplace users to "immediately cancel the transaction" if they spot "any signs of suspicious activity" and to contact police "if necessary".

Tips for buying and selling responsibly can be found here, with people also urged to use their "best judgement". READ MORE: Pervert snared by paedophile hunters after trying to meet child for sex Seller car-jacked during test drive Leroy Simpson A man who advertised a car for sale on Facebook Marketplace was forced to flee the vehicle when a 'potential buyer' pulled out a knife. Callous Leroy Simpson, 44, had used a fake name to arrange a viewing in Great Bridgeford and brandished the blade in a secluded cul-de-sac during a test drive.

The car owner, who was in the passenger seat, fled to safety, and Simpson sped away. A police helicopter was dispatched to trace the car during his ten-mile drive across the M5, which ended by him crashing the stolen vehicle and jumping out at Hopwood Services in .