Gordon Murray is something of a mythic figure in the car business. A former designer of Grand Prix cars for Brabham and McLaren, Murray is perhaps better known as the father of the vaunted McLaren F1 supercar. Since 2007, Murray, who turned 70 last June, has been working on a vehicle that is somewhat less scintillating as the F1, bit that may yet prove more important to the world.

The car made its first public appearance in 2010 as the T.25, and it carried with it some ambitious, even outlandish, design elements. For one, it was very small, but like Murray's F1 supercar, it managed to contain within its carbon-fibre shell space for three humans, a centrally located driver and two rear passengers, whose legs extend to the driver's left and right. “Styling a car to fit three adults is almost impossible,” Murray told James May back in 2012. But his tiny city car, two feet narrower than a Smart ForTwo, does just that. It can be parked nose to the kerb, and three of them will fit comfortably, side by side, in a standard British urban parking space. And the car doesn't have doors. A button on the key fob prompts the body shell to crack open like an egg; the front half tips forward to yield access to the cabin.

Murray conceived more than a car; the T.25 – since renamed the Shell Concept Car for Murray's technical partner and the car's benefactor – demonstrates a philosophy of car-building, one centred on supreme energy efficiency. The car is designed to be inexpensive to build, operate, park and repair.. It uses no exotic propulsion system or impractical concept-car weirdness, but rather an exceptionally frugal three-cylinder petrol engine and a maniacal attention to aerodynamic efficiency and weight-management.

Top Gear's Ollie Marriage recently had an opportunity to take the middle seat of the Shell Concept Car. His thoughts on Gordon Murray's small wonder? "Very polished, complete and clever." But what about that name? "I know, I know, there’s a certain irony that a fuel company is involved in energy saving, but stick with it for a bit."

On Shell's contribution
The message from Shell is basically that if they’re involved earlier and more fully, then the lubrication can be designed in conjunction with the engine, which would help to extend engine life and improve efficiency. Put simply, the thinner the oil, the less friction, the better efficiency. I don’t know how familiar you are with your 15w 40s, but the bigger the number, the more viscous the fluid. The Shell concept car runs on 0w 12. [It's] about the consistency of coffee. I don’t know if we’re talking Italian espresso or instant – I forgot to ask. Anyway, thin oil is part of the virtuous circle that Gordon Murray is so fond of. The car itself used to weigh 627kg, but now weighs 550kg.

On obsessive weight management
[The Concept Car] seats three 95th percentile adults and has a 160-litre boot that extends to 720 litres with the two rear seats folded. And yet it’s only 2.5 metres long and 1.35 metres wide. Way smaller than a Smart ForTwo, small enough to fit on a table tennis table. Weight has been stripped from everywhere: body, suspension, brakes, steering, exhaust, cooling, interior. There’s practically no NVH materials in it. They call it the weight waterfall – removing weight from one area means you can take more from another – so no power steering needed to turn the 145/70 R13 tyres and with only 550kg to shift, outputs of 43bhp and 47lb ft are enough to push it along at up to 100mph. At the moment it uses the old sequential manual from the Smart ForTwo, which is borderline hopeless and results in a 0-62mph time of 15.8 seconds.

In its performance
It feels perky enough off the line and despite being a concept rides competently and isn’t anywhere near as unrefined as I expected. The central driving position is easy to adapt to, the only curious bit being the tall, upright, van-like driving position necessary to make the packaging work. It’s a novel experience. Which is the kindest way to say odd. Despite being predicted to attain a four star EuroNCAP rating, you feel vulnerable because you sit so close to the perimeter. It’s better in the back, shoulders tucked back and legs stretched out past the driver’s seat. Three of us got in and went for a pootle around Dunsfold’s outer road. It was perfectly comfortable. And you can stand up and walk out of it.

On its fuel consumption
On the regular combined cycle it returned 107mpg – remember this isn’t a hybrid at all and nor does it have a start stop system to make the most of idling periods. If it did have one they believe economy would go up another five per cent. Shell didn’t run it on special fuel. I asked if they ran it on V-Power, but no, regular 95 as that’s what people would put in it. They also ran the engine with conventional lubrication – fuel economy fell by five per cent as internal friction in the engine went up by 20 per cent.

On its future
At the moment this is just a test bed – a very polished, complete and clever test bed, but a test bed nonetheless. It would need a bold, forward-thinking manufacturer to step up and take it on because it challenges conventional thinking so deeply. However, conventional thinking has only got us so far and if we’re serious about energy saving, this shows there’s another way.

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