The Mini Cooper S Works and the Mini One D

SPECIFICATIONS

Mini Cooper S Works
Price: £18,079. On sale now
Engine: 1,598cc, four cylinders, 16 valves, supercharged, 200bhp at 6,950rpm
Transmission: Six-speed gearbox, front-wheel drive
Performance: 140mph, 0-60 in 6.6sec, mpg and CO2 not yet quoted

Model Mini One D
Price: £11,390. On sale now
Engine: 1,364cc, four cylinders, eight valves, common-rail turbodiesel, 75bhp at 4,000rpm
Transmission: Six-speed gearbox, front-wheel drive
Performance: 103mph, 0-60 in 13.5sec, 58.9mpg official average, CO2 129g/km

These new-shape Minis seem to be everywhere. That they are ludicrously hefty for something with such a small name, that they have little rear-seat space and even less boot space, and that their prices are far from minimal, seems not to matter.

We cannot judge the new Mini by conventional supermini standards, those of a Corsa, say, or a Fiesta. It is a style object and fun-to-drive toy all of its own, as unique in its way as its miniature inspiration was. Good grief, the new Mini - and it does still seem new - was even voted Car of the Year in the United States in 2002.

So far we have had the Mini One, the sportier Mini Cooper (its extra pace achieved simply with a different engine-management microchip) and the frantically entertaining Mini Cooper S, whose extra potency arrives by means of a neat little supercharger. Now the range is expanded in two directions: one economy-biased, the other maximally fun-biased. Welcome, please, the Mini One D (for diesel), and the Mini Cooper S Works.

The latter has an astonishing amount of power: 200bhp, compared with the already generous 163bhp of the regular Cooper S. That is a lot of motive force from just 1.6 litres.

In the 1960s, racing-car builder John Cooper created the first hotted-up Minis with support from the "works", the British Motor Corporation, home of the Austin and Morris brands under which Minis were marketed. Soon Mr Cooper was running the works racing team of Minis, the cars painted dark green with a white roof and two white stripes on the bonnet.

Nowadays, Mike Cooper runs the company his father and grandfather started, and has developed the Works tuning kit for the new-generation Mini with, of course, parent company BMW's approval. It all helps confirm the Mini's credentials as a predominantly British car: built at Oxford, part-designed by Rover Group people when BMW owned its "English patient", engineering development and sign-off by Ricardo at Leamington Spa. There are other tuning upgrades for the Cooper S, but none has been tested as thoroughly as this official one.

That is why it is so expensive: the Works S costs £18,079 even before you have loaded it with the options beloved of most Mini buyers. (The record so far is around £37,000 for an S Works with every available extra.) A standard S starts at £14,605, so the premium is £3,474. For that you get a freer-flowing cylinder head and similarly enhanced exhaust, a new supercharger whose compressor rotors are Teflon-coated and spin faster, a revised microchip to make it all work properly, and of course some extra visual sportification.

The Cooper S is already very lively, more so than it feels, because the supercharger gives such an even power delivery with no particular fireworks-arrival point. Sometimes, you crave just a little more: you get spoilt. The Works obliges, with an effortless torrent of instant muscularity from low revs right up to the top of the speed range and an accelerator response sometimes verging on the savage. The sound-effects match the thrust, with a louder and higher-pitched version of the supercharger whine that is so redolent of an original Mini's gear noise, and a deeper, crisper, harder exhaust note.

Here, you feel, is a Mini with enough of an engine to trouble the breed's glued-to-the-road suspension, but all that power arrives on the road surprisingly tidily. The steering is as precise as ever, the extra energy coursing through the front wheels helping to overcome the slightly viscous response felt in lesser Minis, and the firm suspension and fat wheels make this a fabulous car to flick and squirt through traffic. Yes, you can still have fun driving a car in 2003.

Perhaps surprisingly, the Works also copes equably with bumps, especially if you stick with the standard 16ins wheels instead of glamorising your Mini with the racier-looking but less absorbent 17ins options. Add solid build quality, a precise and quick-acting six-speed gearbox and and you can almost justify that price.

If you are the sort of person to succumb, you probably will not be drawn to the Mini One D. This is the sensible face of the Mini world: less Mini adventure, more Mini budget. It costs £11,390, which is £985 more than a petrol Mini One but still cheaper than the non-S Cooper. Most diesel cars have an engine size bigger than their petrol counterparts in a range, but the opposite is true here because the diesel's pistons displace just 1,364cc. Like the petrol motor, which comes from Chrysler's Brazilian factory, the diesel comes from an outside supplier: Toyota, whose Yaris supermini can also be so powered.

This all-aluminium engine delivers 75bhp and a respectable 132lb ft of pulling power, more than a Cooper, if not a Cooper S. But, despite these promising figures, something is missing in the One D. The engine sounds quiet for a diesel, and long-legged gearing makes it a very relaxed cruiser (it shares the S six-speed transmission, albeit with revised ratios), but the instant eagerness so vital to a Mini's being is absent. You have to wait for the turbocharger to spin up to speed before the engine can set free its pulling ability, and by then the traffic-gap has gone. That is a pity, because the figures reveal this to be a frugal fashion accessory. Gentle driving should squeeze nearly 60 miles from each gallon of diesel oil, far removed from the considerable thirst of the supercharged S models. But there are three more downsides to the One D.

The first is that the front seats, obviously shared with the petrol One, have an oddly convex backrest which sabotages lateral support. Maybe they will soften with age. The second is that, surprisingly, the ride over typical urban ridges and potholes is more agitated than the ostensibly firmer S's. The third is that the (optional) air-conditioning pump's monotone drone gets so annoying you have to turn it off and swelter.

If you just want the style, and economy is important, the One D makes sense. To me, though, it just seems a waste of a good Mini.