From the driver’s seat, the most obvious clue that you’re sitting in an electric Mini is the big dial behind the steering wheel. A sweep hand falls inexorably from 100 to 0 as you pile on the miles. Below this analogue dial is a small digital trip computer, which can be set to display remaining range in miles.

BMW quotes a notional range of 100 miles per charge of its Mini E (it actually quotes 100 to 120 miles and 156 in ideal conditions, but with electric cars we’ve learned to look at the lowest number and work downwards). This means that the big dial ought to render the range predictor redundant – at 100% charge there should be at least 100 miles of motoring to go, and at 50% charge there should be roughly 50 miles remaining before you need to find a socket.

Only of course it doesn’t work that way.

We put the electric cabin heater on for five minutes at the start of our hour-long Mini E road test, and drove the whole route as we would a conventional fossil-fuel car. We soon saw the range prediction and the battery meter part company. After 32 miles on urban and rural roads, the range was down to 47 miles, while the dial said 55% remaining.

Still, we suppose about 80 miles of electric motoring with warm toes isn’t bad, all things considered.

The Mini E is a development vehicle, rather than a potential product in its own right. BMW says it intends to launch a four-seat electric car “within the next four years”, and the Mini E is a mobile testbed for this “Mega City Vehicle”.

Roughly speaking, we have a standard Mini with a motor and control electronics in place of an engine, and a huge battery where the back seats used to be.

The battery weighs about a quarter of a tonne, and is conceptually similar to the power unit developed by Tesla Motors. Unlike, say, the bespoke flat-laminate batteries Nissan and Renault are making for their electric cars, the Mini and Tesla route to electrification is to buy job lots of cylindrical lithium-ion cells, of the kind usually destined for laptops. But whereas a MacBook might use three cells, the Mini swallows more than 5,000 of the things – built up in 48 bricks of 106 cells each. Overall, this power pack stores 35kWh, of which about 30kWh can be drained during normal driving, fed to the front wheels via a 150kW (200bhp) motor.

The Mitsubisi i-Miev, for comparison, carries 16kWh and a employs a 47kW motor, while the Tesla Roadster has 56kWh on board and a 185kW motor. BMW is also keen to point out that 200bhp is more than the Mini Cooper S can muster – its 1.6-litre petrol engine peaks at 175bhp.

The Mini E does indeed feel fast, but not Cooper S quick – carrying the 260kg battery is, after all, like having two 20-stone friends on board.

Climbing in, you first have to remember to open the correct door – all Mini Es are left hookers. Slot the electronic keyfob into its dashboard recess, and press the small stop-start button. The battery gauge swings into life as the power pack readies itself in complete silence. The cells are actively cooled, with air drawn through a grille behind the front seats and expelled under the car, but we couldn’t detect the whirring of fans.

The gear selector is standard auto stuff – push down on the brake pedal and depress the chrome safety catch to pull the lever back into D.

Release the brakes and – nothing. The car won’t creep forward until you give it a tickle of throttle. Once on the move, the car pulls away strongly but very controllably, with plenty of urge on offer. Give it a bit of welly and the car will just squat and go, producing a very satisfying turbine-like whine. Nought to 62mph takes just 8.5 seconds, and we have no doubt that the car will reach its limited 95mph top speed.

Actually, the delivery is not entirely clean and linear. Feed in power gently and you won’t notice any gaps, but stamp on the throttle from a standstill – lunging for a gap on a roundabout, say – and the car will pause, motionless, for just long enough to send your heart to your mouth.

There’s a similar non-linearity to the regenerative braking. The regen is set up much more aggressively than in other electric cars we’ve driven – it doesn’t feel like conventional engine braking, it feels like you’re pressing the brake. But this unusual response takes half a second to arise – lift off suddenly and press on again in less than half a second and you won’t slow down at all.

This makes for an unusual driving style that takes some getting used to. In normal driving you don’t touch the brakes at all – you drive everywhere simply by adjusting the throttle. Sensibly, BMW has set up the Mini so that the brake lights come on as soon as you lift the go-faster pedal.

According to Alexander Thorwirth, head of alternative drives at BMW, aggressive regeneration is the optimum approach, even if it feels odd. “We will see how it goes in the trial, but we think electric cars require some behavioural change and that includes adjusting to how the vehicle works,” he says.

We get where he’s coming from, but we wonder if it might be dangerous to adapt to a driving style where you rarely touch the brakes.

Odd pedal actions aside, the Mini E felt like a very mature package – much closer to a viable production vehicle than we’d expected. It’s very fast, reasonably responsive, handles and rides well and feels as agile as a Mini should. The range might be limited, but no more so than other electric cars.

True, there are no back seats and no boot to speak of – a suitcase would have to travel atop the battery.

We’re not sure we’d want to spend £330 a month to lease a Mini E though, particularly not in a six-month market trial. But apparently there are lots of people willing to pay handsomely to help BMW do its R&D – more than 500 people applied for the 40 places available on the UK trial. The shortlisted applicants will be hearing from BMW very shortly, apparently.

We wish them luck, and we await more news of the BMW Mega City Vehicle with interest.

At less that 3 metres from its button nose to its non-existent boot, the Toyota iQ is a very short car. You know that, intellectually, when you climb aboard, but you still struggle to get your head around the full extent of its lack of length.

A case in point: parking our iQ at the roadside, nosing in towards the car in front, we stopped at what felt like a sensible distance. Then we got out and saw that we’d left a yawning gap almost large enough to slot another iQ in. So we jumped back in. From the driver’s seat, the gap still looked and felt about right – you can’t see any of the car’s wee little bonnet, of course. So we nosed a bit further forward – towards what felt like imminent contact between our toes and the car in front. Satisfied, handbrake on, engine off, we jumped out. And there was still enough of a gap for an amorous couple to stroll through, arm in arm.

So owning an iQ requires a recalibration of the senses. And, thinking in the other direction, it’s also probably not a good idea to spend time in an iQ and then to leap straight into something with a long and expensive prow. We suspect Aston Martin’s notion of a dollied-up iQ as a town runabout for owners of its long and low machines is not such a good idea.

Perhaps our inability to think sufficiently small is proof that Toyota has succeeded in its goal of building a small car that feels big. There’s certainly plenty of width on offer – the iQ is comfortably wider than most city cars, and elbows are unlikely to feel hemmed in.

What was absent during our iQ road test, sadly, was a real grown-up car feel. There are too many of the little things missing that you’ll find in every big car these days.

It sounds trivial, but the vanity mirror in the sun-visor is not illuminated, for example. The seatbelts aren’t height-adjustable. The steering wheel feels lovely but doesn’t adjust for reach. And there’s no centre armrest option, despite a noticeable gap between the seats where one would happily fit.

In fact there’s no enclosed storage anywhere in the car – no glovebox, no centre-console cubby, no seat-back pockets – not even an ash-tray. There are long, unlined plastic bins in the doors, of course, and a cupholder between the seats, and that’s your lot. Coins for parking will need to travel in your pocket.

Overall the interior is a huge let-down, for those thinking of downsizing. Switches feel reasonable, but the larger plastic surfaces are kind to neither the eyes nor the fingers. Seat adjustment is by awful ratchety lever, and after sliding a seat to and fro to gain access to the rear you will find the seat-back has returned in its bolt-upright default. We failed to find a single fixture or fitting that surprised or delighted.

Rear-seat access is OK, and there is indeed enough room in the car for three and half adults. Although with a full complement aboard, nobody but the driver will be comfortable, and luggage will have to stay at home. Viewed as a two-seater with jump seats, though, the iQ makes perfect sense – and this approach will happily minimise the need to fight with the seat ratchets.

We drove a top-spec 1.3-litre car with the optional Multidrive continuously variable gearbox. We like CVTs, and slotting this one into D and forgetting about it is the perfect preparation for crawling the urban sprawl. Two-up, the car feels perfectly eager and engine noise is only intrusive if you floor it. The 1.0-litre car weighs 85kg less than the 1.3-litre version, coming in at just 845kg, making the bigger and more expensive engine something of a moot point.

Given that the motor must be about six inches from your knees, the interior is remarkably quiet and refined, and the ultra-compact aircon unit works very well.

The steering feels light and direct with typical Toyota numbness. The turning circle is an incredible 3.9m – much tighter than a London Taxi’s – but the helm still feels steady and predictable at speed.

We were surprised at the high quality of the ride on offer. Even with the iQ3’s 16-inch wheels the car felt very comfortable over small lumps and bumps – although there is often the unusual feeling that both the front and rear axles are lifting and falling at the same moment, rather than one after the other. Bigger surface imperfections and speed humps do provoke noticeable pitching, but that’s unavoidable in a car with a 2-metre wheelbase.

Relatively high-set seats help to combat any feelings of vulnerability created by piloting such a puny vehicle, as do the multiple airbags and the five-star NCAP rating.

Our test car was fitted with every bell and whistle going, making for a rather expensive experience. The base 1.0 manual costs from £9,615 and is relatively generously equipped. For our 1.3 engine add £2,000 (which also gets you climate control, keyless entry, auto headlamps, bigger wheels and chrome mirrors). Then add £400 for our grey mica paint, £1,000 for the auto box, £345 for mats, £690 for leather seats, £495 for a stupid spoiler and skirt, and £930 for the full satnav, Bluetooth and iPod experience. All in all, that’s a surprisingly hefty £15,475. In other words, a lot of money for a tiny, two-seat runabout.

There’s a lot to like about the iQ, but in the end it left us unconvinced. It’s not plush or posh enough for well-heeled drivers hoping for the perfect city runabout. They’ll still go and buy a Mini. And it’s too compromised for people who would otherwise spend the same money on a Fiesta or Corsa. It’s a better car than its Aygo sibling, but it costs a heck of a lot more to buy.

So for the moment there are some nearby stools, but this little car seems to be falling between them. And, unusually, all the problems are on the inside. We wonder if an early interior facelift might be in the works at Toyota HQ.