Aygo is smaller than Yaris but that's not stopped Toyota from turning it into a supercar.

Making its public debut at the British International Motor Show in London, it's a one-off model, a "shopping supercar" that owes more to rallying than drifting. This is a car that's about the joy of driving: with no electronic handling aids, no power steering and no ABS, it's intended to be like a kart with doors and a roof.

Recognisably an Aygo, it clearly packs more muscle with its custom-made body, 17-inch alloys and beefy Goodyear 225/45 rubber. There's even a direct link to Toyota's sporting heritage as Crazy's carbon fibre rear wing is a part taken directly from the race cars in the American Champ Car series.

Aygo Crazy is fettled with the Toyota 1.8 VVT-i unit that powered the final generation Celica and MR2 Roadster, rear-mounted and driving the rear wheels through the Roadster’s five-speed manual gearbox. The addition of a Toyota Motorsport turbo conversion kit boosts power output to 149kW and torque to 240Nm, compared to the 47kW and 93Nm mustered by the standard road-going version.

To cope with the greater engine performance, a bespoke cooling system has been designed, with a huge, front-mounted aluminium radiator.

Weighing in at 1050kg, Aygo Crazy is capable of an estimated 200km/h, but speed isn't its defining quality: this is a machine designed to be responsive and alive to the driver's commands.

The suspension is from the MR2 Roadster, with MacPherson struts front and rear. Adjustable Tein dampers sharpen dynamic performance and the front and rear track are one inch wider than on a standard Aygo.

The cabin, finished by specialist coachtrimmers O’Rourke, features purpose-built sports seats with four-point safety harnesses and a full roll cage.

With its bold Aygo Crazy decals and T2 4YGO (turbocharged, two-seat Aygo) number plate, Aygo Crazy will be hitting the show circuit — and the open road — in the coming months.