The Big Mouth meets...

The Big Mouth meets the Big Mac! In an amazing world exclusive, Auto Express was on hand to witness US TV chat show host and car collector, Jay Leno, hit the road in the machine every supercar fan is desperate to climb aboard: the McLaren MP4-12C.

The first of a new line-up of road models from the famous racing outfit, it follows in the wheeltracks of the legendary F1. And it will go up against the Ferrari 458 Italia when it reaches showrooms in 2011. We joined Leno at the Dunsfold test track in Surrey, where engineers were putting MP4-12C prototypes through their paces.

Leno got the offer of a ride on two accounts. For starters, heтЂ™s interested in one of the new models. Secondly, a trip here is a rare thing for him. He was last in the UK 10 years ago, and that was also for a visit to McLarenтЂ™s HQ in Woking, Surrey тЂ“ when he bought an F1 road car.

тЂњI thought it was quite an honour to be given this chance. It was a real thrill,тЂќ said Jay at the windy airfield perimeter track. тЂњIf you are a soccer fan, itтЂ™s like being asked to play with Manchester United.

тЂњSo when you are with your car friends and they say тЂ�I wonder what this new McLaren is likeтЂ™, you are able to tell them you were in it тЂ“ and at that point, the conversation just stops!тЂќ

The MP4-12C is a real technological tour de force. It has a 600bhp 3.8-litre twin-turbocharged V8 engine, while its carbon fibre chassis weighs only 80kg. Other highlights range from a seven-speed twin-clutch gearbox to double wishbone suspension with adjustable dampers. Driver aids include brake steer, which applies the inside rear brake as the car corners, to aid turning.

WATCH A VIDEO OF LENO RIDING SHOTGUN IN THE MCLAREN MP4-12C HERE.

After getting a tour of the factory with McLaren Automotive boss Antony Sheriff, Leno was taken to a secret viewing room to see the car, which still bears an early version of the nose. тЂњI like the proportions,тЂќ he said. тЂњToo many road cars now are big and wide. ItтЂ™s better looking than the Ferrari, and I think it has a unique pedigree. Everybody knows Ferrari; only real enthusiasts know McLaren.тЂќ

The icing on the cake for Leno was the chance of a chauffeur ride with factory test driver, Chris Goodwin. тЂњHe told me the camouflaged prototype car was in the middle of its development programme, and that they were honing its ride and handling,тЂќ explained Jay. тЂњApparently, Dunsfold is good as it has loads of different corners. ItтЂ™s bumpy, fast and slow, with lots of changes of direction.тЂќ

Leno then strapped himself into the cockpit тЂ“ and with a thumbs-up, he disappeared in a blur as Goodwin planted the throttle and lit up the tyres.For an hour, first in the dry and then, after a thunderstorm, in the wet, Leno and Goodwin lapped Dunsfold at full speed.

Leno doesnтЂ™t normally make a good passenger, but in the McLaren itтЂ™s the best seat in the house. Plus, this is the closest anyone outside the firm will get to the new car for months to come. Jay grinned uncontrollably as he was brought to a halt and climbed out. тЂњFrom the passenger seat, it feels amazing!тЂќ he reported. тЂњItтЂ™s obviously not a finished car, but acceleration is extremely strong and the engine revs to 9,000rpm.

тЂњThe gearbox shifts very quickly, too тЂ“ certainly faster than a human could shift. ItтЂ™s all a sensory overload, but not in any sort of scary way. тЂњThis is the first car that has forced me to accept that paddleshift is the future. I much prefer a mechanical gearchange тЂ“ like a mechanical watch. But Chris GoodwinтЂ™s changes were sublimely smooth and fast.тЂќ

The car Leno rode in is stripped bare and crammed with test equipment. But he still assured us that itтЂ™s a great place in which to spend time, with the two-seater offering lots of space, despite having one less seat than his McLaren F1.

тЂњVisibility is good,тЂќ he added. тЂњItтЂ™s a modern, practical car тЂ“ not a dream machine that you couldnтЂ™t live with. It appears to have good ground clearance, so you should be able to use it in most places. From inside, the sound was snarly but pleasant. Any time you have twin turbos you get a bit of a muted sound.тЂќ

The greatest compliment Leno paid to the 12C was by comparing it to a model from one of BritainтЂ™s greatest auto brands: Lotus. тЂњIt felt like the kind of car [Lotus founder] Colin Chapman would have made if he was still alive,тЂќ he said.

тЂњOnly when youтЂ™re on the move do you sense how light it is. Yes, it has a carbon fibre tub and the lightest technology out there, but that lightness really translates to the road. тЂњIt felt nimble, precise and accurate тЂ“ all the things a Lotus is famous for, but in a package that is uniquely McLaren. I love the fact they have fought to get the car under 1,400kg. ItтЂ™s a revelation in this day and age.тЂќ