This is Subaru's ultimate incarnation of the road-going Impreza, fettled by Cosworth to produce 395bhp and offer supercar-rivalling acceleration.

The Cosworth Impreza STi CS400 can get from 0-62mph in just 3.7sec, matching a Lamborghini Gallardo LP560-4 and beating the Ford Focus RS’s time by more than two seconds. Top speed is limited to 155mph.

The standard STi’s 2.5-litre turbo engine gets high-performance pistons, high-strength steel conrods, Cosworth-spec engine bearings, a redesigned head gasket and a high-pressure oil pump. The turbocharger has also been modified, with a new compressor design and wastegate actuator.

A Cosworth-designed exhaust system and a remapped ECU complete the revisions, which also boost torque to 398lb ft.

The chassis is a joint effort between Cosworth, Bilstein and Eibach. The Impreza gets new coil springs and its ride height is 10mm lower. The front brakes are larger (355mm) AP Racing discs.

Styling tweaks include a new front bumper, foglights, mesh grilles and rear spoiler, and new 18in alloy wheels that help to widen the tracks by 12mm.

Inside, there’s a piano black centre console, privacy glass and new Recaro front seats.

Just 75 examples of the car will be made, all in right-hand drive and purely for the UK market. It’s available in just three colours: silver, dark grey and red.

The car will also be comfortably the most expensive road-going Impreza yet, at £49,995.

John McIlroy