Spy Shots: Mystery supercar spotted, what is it?

CAR online has a mystery car on its hands. They've acquired spy shots of what appears to be a new supercar undergoing testing at a UK facility, but have no idea which supercar it is. Their first guess was the same as ours – the Lotus Esprit, though the actual car that comes won't be called by that name. However, after some detective work, it's unlikely this car is the next mid-engine Lotus. It seems that the car is registered as having a 7.0L engine, which has some thinking there's a Corvette mill back there. Unfortunately, there would be no reason for the next Lotus Esprit to be testing with a giant American V8, as those cars were known for their smaller, lightweight engines. Lotus, however, is no doubt involved with the car, as paperwork bearing its logo was seen in the car's cabin. But Lotus does work for many manufacturers, so it could belong to one of its clients. The names Noble, Ascari, Audi, McLaren and Mercedes have been thrown around, but that's merely a list of automakers that have supercars under development. Any guesses? Leave them in the comments.
[Source: CAR online]