The all-electric Mini E bursts away from traffic lights, zooms about like a sports car and can carry you 120 miles on a four-hour charge. A milk float? In your milkman’s dreams. Unfortunately, your milkman can’t have one — not unless he signed up to be one of the 20 triallists, dwelling between Oxford and London, who will shortly take delivery of a prototype Mini E and live with it for six months. A second trial group of 20 will repeat the experiment next year. After which, BMW and its consortium partners will know a lot more about whether electricity genuinely is the future of the city car. And then, come 2015, BMW may or may not decide to bring an electric vehicle to market, which may or may not be a Mini.

Early and tentative days, then. And accordingly the event this week, at which the press were let loose on the Mini E, had something of the flavour of a Montgolfier balloon trial, circa 1783, albeit with better refreshments. You partly expected to see people in waistcoats and breeches, stroking their whiskers and muttering: “That’ll never fly.”

It does, though. It goes like the electric clappers. Moreover, unlike previous electric vehicles, it looks recognisably like a car — indeed, better still, like a recognisable car. The great failure of all electric models to this point has been their weakness in encouraging desire. How much wider a take-up might there have been for the gawky G-Wiz if it didn’t resemble something that Laurel and Hardy had just driven through a sawmill? It’s been like the old joke about Superman. If electric cars are so smart, how come they wear their underpants outside their trousers?

This one, though, corrects a million consumer impressions at a stroke, sending most of the usual covetable Mini signals. It’s got the Mini’s bodywork and the Mini’s dinner-plate dials and silver toggles, but not, alas, the Mini’s rear seats. That space goes to the battery, making the Mini E an almost boot-less two-seater, rather reversing, one might feel, the original genius of Sir Alec Issigonis’s tiny car for four. Still, maybe one day we will laugh at these early cells, the way we laugh at computers that filled whole rooms, and the space can be restored to passengers.

One of the criteria for participation in the trial was access to a garage, but for most of us who live in cities, the garage has the status of a creature from myth. We’re told they exist, but very few of us have seen one, or been inside it. Southern Electric is proposing a “network of public charging points”, but if you can’t get a cable from your home to your car, won’t the golden age of convenient electric motoring be fairly short-lived for you?

So many unknowns, though, at this larval stage. Will the battery hold strong and proud across the lifetime of the car, or will it be like the one in my laptop and get fed up eventually, meaning I have to replace it at disproportionate cost? Will the stress on the grid yielded by 20 Mini owners recharging their cars overnight lead to unforeseen power outages in the Whitney area? Who will be the first Mini E driver to conk out in a contraflow on the M40 and create a 56-mile tailback to Banbury? And why isn’t BMW putting this energy into hydrogen, the properly post-carbon alternative?

All this and more remains to be discovered. But as pioneers (ballooning and otherwise) have always understood, if we never try, how will we know?

Mini E

Price: Not for sale

Top speed: 95mph (limited)

Acceleration: 0-62 in 8.5 seconds

Engine: 201HP electric

Range: 100-120 miles

Charge time: 4 hours at £1.50-£2 a time

Rating: 4 stars

The people’s icon plugs in to send a shock through the clean-driving sector