Big Mac prepares to blow its top

Fancy feeling the wind in your hair... at 207mph? That's the incredible prospect awaiting potential owners of the McLaren Mercedes SLR convertible - a car that has remained top secret until now.

Auto Express has learned a drop-top version of the car built in Woking, Surrey, is well on its way to production, and will be officially unveiled within six months.

It follows in the wheeltracks of the Vision SLR concept car, and will use the same 626bhp V8 as the standard model. With McLaren's composite body, the SLR convertible will be as strong as the fixed-roof version, and its performance just as explosive. Prices start at a hair-raising £350,000.