Mercedes has announced the starting price of the new SLK 55 AMG, which is now available to order through franchised dealerships.

At £54,950 on the road, it undercuts the BMW M3 convertible by around £4,000. The M3 has four seats and a similar power output, but can't match the SLK 55 for outright pace. It's not a purpose-built convertible, either, unlike the SLK.

The Mercedes is almost £10,000 more expensive than a Porsche Boxster S, though, albeit bringing much greater performance from a naturally-aspirated 5.5-litre V8 engine with 415bhp, compared to the Boxster S's 311bhp 3.4-litre six-cylinder unit.

There are few other direct rivals for the SLK AMG to consider. The Lotus Evora S costs about £7,000 more and delivers similar performance from a supercharged V6, but at the moment the Mercedes has territory all to itself.

Some of the new car's noteworthy characteristics include a cylinder shut-off system that effectively turns the V8 into a V4 when used at light throttle loads. That contributes to a 30% reduction in fuel consumption and emissions.

With performance figures including 0-62mph in 4.6 seconds and a limited top speed of 155mph, the car's claimed economy figures of 33.6mpg and 195g/km are very impressive.

Leather seats are standard along with all the AMG styling components, AMG suspension, the excellent COMAND online interface and DAB digital radio.