Citroen's task was simple: create a totally basic vehicle that was essentially four wheels under an umbrella, able to carry four people in comfort plus 50kg of potatoes at 60km/h (37mph) on unmade or pave roads - or a basket of eggs over a ploughed field without breaking one.
The result was the roly-poly, long lived but ultimately trendy and much loved 2CV deux chevaux. By 1939, 200 prototypes had been built and the odd-ball stayed in production until 1990.
Now Citroen is at it again but customer expectations have changed: the no-frills C-Cactus diesel-electric hybrid concept may also have four wheels but they are under a panoramic polycarbonate roof and the interior is air-conditioned. Like the 2CV, it is able to carry four people in comfort and lugging 50kg of potatoes would be a doddle. For ecological reasons, top speed is limited to 93mph.
Although ploughed fields are out, the C-Cactus could carry a few dozen bottles of Beaujolais across Europe, not only without breaking one but also without leaving a broad carbon footprint. It is super-economical, averaging about 83mpg and with emissions down to 78g/km, way below any scheduled official requirement.
Driving the C-Cactus is a weird experience. I had a nagging feeling that something was missing - like the dashboard. Not necessary, apparently. Passenger airbag? Not necessary. The glovebox? Hang a bag on a hook shaped like a butterfly brooch. Window switches? The windows don't open.
The air-conditioning system is there but forms part of the interior styling, looking like the intake of an airliner's turbofan engine, or possibly a hairdryer for the super-follically endowed. The steering column is exposed and the transmission selector is a simple "ego" switch: "Push it like this and the car 'e go forward . . . like this and 'e go backward." The floor of the C-Cactus is upholstered in recycled leather offcuts, its hollow door panels have wool trim and door exteriors are unpainted. The rear seats simply slide forward and slot beneath the front seats to enable more potatoes to be carried.
If it all sounds boringly basic, it isn't, because instead of just designing a no frills, worthy car devoid of comfort or aesthetic appeal, Citroen has used its minimalist approach to maximise its attractiveness, like a sort of mobile Pompidou Centre. It may look pug ugly at first glance, but I warmed to it on my drive near Paris.
Emmanuel Lafaury, Citroen's technical manager for concept cars, explained how the number of interior components was halved: "The car just has what is essential: attractive design, air-conditioning, a high-quality audio system, cruise control - and full safety systems. We used the same moulding [the concept is of carbon fibre] for part of the front of the car and for the rear. Crash safety is not a problem and we think that a limited top speed of 150km/h [93mph] is fast enough, so we don't have to have such large and expensive brakes." Diesel and electric motor work together for maximum acceleration.
Abandoning everything that is not essential helps to reduce weight and particularly offset the cost of the C-Cactus's highly efficient but equally highly expensive diesel-electric hybrid drive system and indicates how the philosophy could - and will - be applied to a production car. In city traffic, the Cactus just runs on its electric motor.
Mass produced in a rather less extreme form, the C-Cactus, which is based on the Citroen C4 Picasso platform, could sell at about the same price as today's most basic C4 - about ?12,000, but the running costs would be sensationally low and it could become as trendy as the quirky 2CV.
Cathal Loughnane, the Citroen interior designer, said: "The C-Cactus has been created in the spirit in which the 2CV was conceived. Every aspect of it serves a necessary function. But this time, we have avoided the look of a cheap car."
If Citroen could keep its nerve and plant the Cactus on the market soon, there would be no real competition; it could be in an un cheval race.
Variation on a theme
Car Citroen C-Cactus concept
Engine 1.4litre 70bhp turbo-diesel plus 30bhp electric motor
Transmission Five-speed robotised manual
Performance Top speed 93mph (electronically limited), 0-62mph approx 10sec
Fuel consumption (combined) 83mpg
CO2 emissions 78g/km
Price As a one-off concept, about a million euros (?747,000); in production ?12,000