Some of what makes this car tick is already familiar through the i3. Both cars have a structure largely made of carbon fibre reinforced polymer, a material that’s 30% lighter even than aluminium, tall and narrow aerodynamic wheels and a body shaped to flow the air as efficiently as possible.

You could argue that hinging the doors on the A-pillar is a bit of a gimmick but, with a low roofline and a sill that’s higher than the front seats, conventional doors would make it almost impossible to get out of the car in most parking spaces. Plus, at 1,490kg, that lightweight structure means this is 65kg lighter than the Porsche 911 Carrera 4 GTS it’s up against, and only 22kg heavier than a Renault ZOE.

That’s good going for a car with two power sources, each with a gearbox and energy storage. This pairing combines a 231hp 1.5-litre three-cylinder turbocharged petrol engine at the rear wheels, and a 131hp electric motor at the front axle, allowing fully electric driving but with 362hp and four-wheel drive available with a firmer press of the throttle.

It’s very clever in the way it uses these two. If there’s range in the battery, the Comfort and ECO PRO driving modes default to using the electric motor and, fully charged, the i8 can reach 75mph or cover up to 22 miles without burning any fuel. With adaptive suspension, comfortable seats and almost no drivetrain noise, it’s remarkably comfortable too.

Select Sport mode and the i8 transforms. The petrol engine gives out a hard metallic growl and everything sharpens in response, the combination of combustion engine and electric motor hauling the lightweight supercar towards the horizon with smooth but blistering urgency. Even the all-digital instrument display changes colour to match.

It means the car can use both power sources as efficiently as possible, to get full power, top up the battery, or even to provide four-wheel drive traction when needed, and any spare energy from the engine is stored as an electrical charge when cruising. But, where possible, the petrol engine spends most of its time doing nothing.

However, while the i3 is a predominantly electric car with the option of a range-extender, the i8 is really a hybrid supercar with a bit of electric range. The battery capacity, at 5kWh, is around a quarter of the i3’s, and in turn this means there’s been no need to equip it with a rapid charger. It takes at least three hours to regain 80% of its electric range.

Plus it’s also not quite present-day technology, even for even the most determined potential customers. Demand has outstripped supply so extensively that the earliest you could expect to park one on your driveway, if you headed down to your local dealership and ordered today, is September 2015. Even nearly new examples are trading for significantly more than the list price.

But those early adopters are in for a treat, because this is one of the most fascinating four-wheeled machines money can buy, packaged in a design which does a better job of turning heads than vehicles two or three times its price. The future really is as interesting as we’d been promised.

Verdict:

As fascinating to drive as it is futuristic to look at, the i8 is as important to BMW as the R8 was to Audi back in 2008. Conquest sales beckon.

Specification:

Sector: Supercar

Type: Petrol-electric plug-in hybrid

Price: £94,845 (after £5,000 govt grant)

Fuel: 135mpg

Electric range: 22 miles

CO2 (tailpipe): 49g/km

Charging port: Type 2