Watch Scrapheap Challenge online: Episode 12 Grand Prix

Grand Prix They're back! That's right, our reigning champions the Cat-alysts have resurfaced to see if they can make it a hat-trick and beat the Destroyers, our 2003 series winners, in this week's extravaganza. All they have to do is build a single seat, open-cockpit racing car. But will they be able to outwit our cunning Royal Navy team and retain their title? Destroyers Our Royal Navy boys James Ellis, Adrian Eason-Bassett and Jason 'JJ' Swift have already seen off The Squadron, Ging Gang Goolies, Cops and Bodgers and our surprisingly handy estate agents, Hot Property. Joining them for this jaw-dropping grand final is Nick Jordan, an engineer with more than 30 years of working experience of motor sports for teams such as Lola. Can he help our Destroyers take on the wily Cat-alysts and steal the trophy from under their whiskers? Cat-alysts There's barely any need to introduce these boys as they are becoming part of the Scrapheap furniture. These car-flinging champs saw off the Barley Pickers last year and the Megalomaniacs the year before that. But never let it be said we don't have any manners here at Scrapheap ? The Cat-alysts are all engineers at the Jaguar factory in Warwickshire. In his spare time Garry Preece, the team captain, has an obsession with antique bathroom taps. Tim Wright is into motorcycles, scuba diving and snowboarding. Shane Brading's bodging career began at the tender age of 13, when he converted an old Volvo into a banger racer. Helping the Cat-alysts in the 2003 grand final is Matt Feasey, part of the design and development arm of the Cosworth Formula 1 team. Matt has rebuilt several cars and often builds bits of test rigs at work but hasn't ever built a vehicle from scratch. The expert Rob Taylor is the Chief Engineer at Jaguar Formula 1. He's worked in F1 for about 15 years and has worked at many of the big names such as Jaguar, Ferrari, Arrows and Benetton.

click here to see where to watch or .