The Cooper Car company was founded in Surbiton in 1947. Charles Cooper and his son John began building racing cars that eventually changed the face of F1. In 1961, John Cooper conceived the first faster-and-tuned Mini, which dominated rallying in the 1960s. The rest, as they say, is history.

Cooper is a name that became synonymous with Mini, and in 2000, John's son, Michael Cooper, founded John Cooper Works, which made racing tuning parts for the reborn, BMW-built Mini. In 2008, BMW bought the company outright and now the John Cooper Works Mini is built in the Mini factory in Oxford.

So is the fastest, highest performance stock Mini you can buy worth the extra outlay?

Agile, small, nimble and powerful: the Cooper-tuned Minis have always possessed qualities that simply made them put a smile on your face. Small enough that they felt pocketable but with performance that made it feel like a rocket, the fast Minis defined the term pocket rocket.

Pocket-lintMini John Cooper Works - 6 copy

Thing is, the 2014 refresh of the Mini ushered in a new platform shared with BMWs. So this third-generation new Mini (codename F56) is no longer a small car. At 3.8m long and 1.7m long, it's a bit of a bruiser.

Despite those growing dimensions it still achieves pocket rocket status though. The John Cooper Works - or JCW as it's usually referred to - is one of the most fun-to-drive cars we've driven all year. It begs to be taken by the scruff of the neck at any given opportunity and thrashed down your typical British back road.

There are a few factors in the mix that make it a giggle to drive. First up is the engine, which is a fizzy, powerful thing. It's BMW's 2.0-litre turbo unit, and we know from driving it in other BMW products that it's an excellent engine. It suffers from little turbo lag, pulls hard from low down, revs out happily to its 6,500rpm limit, and makes a decent noise while doing it.

Any gear, any situation, press the throttle and the Mini thrums forward. But stick it in 6th gear, trog along the motorway at 70mph and it'll return 40mpg (maybe more). Its 0-62 marker is 6.3-seconds - but it feels faster. Rumour on the internet has it that these 2.0-litre BMW turbos tend to make rather more than the 228bhp that the company claims.

Pocket-lintMini John Cooper Works - 24 copy

Most importantly given the price lift over the regular Cooper S, the JCW feels like a more significant performance step forward than the figures suggest.

Minis have never been just about their engines and power. Far from it. The Mini's wheel-at-each-corner stance, low weight and keen handling are the things that have made them feel like pocket rockets.

Mini is even playing on this factor with its latest mode selector, which in sport mode pings up a "maximum go kart feel" message on the centre screen. Twee though that might sound, get the JCW in sport mode on the right road and it does feel like a go kart, responding keenly to your every input (the steering rack is fast) and feeling like the car is pivoting around you.

Pocket-lintMini John Cooper Works - 30 copy

The front of the car is keen to turn in and, generally speaking, sticks like glue to the road thanks to the electronic differential and some sticky Dunlop tyres. It's perhaps not as keen as some mechanical differential-equipped rivals, and in damp conditions you can provoke understeer - where the front of the car pushes wide of your intended line. There's fun to be had in lifting the throttle and getting the whole car to tighten its line when this happens, turning you into a corner. Agile is the word that comes to mind - and it's helped out by the adaptive dampers which were optionally fitted to our test car.

The JCW has stiff suspension, which we suspect might get tiresome on some poorer British roads in its standard form. The adaptive dampers offer adjustability, though, meaning you can have the engine in sports mode, but the dampers in comfort (softer), and they make the ride more than tolerable. It is annoying the dampers are an optional extra though. But at just £240 they aren't overly pricey and are an extravagance worth having.

Joining in the fun is the sports exhaust system - which is amusingly boisterous. The regular Cooper S Mini will occasionally throw in a pop when you back-off the throttle having revved the engine out. Do the same thing in the JCW and it sounds like someone's thrown a load of (admittedly quiet) firecrackers out the back. We've been talking about this characteristic on a lot of performance cars recently, and remarked that it can get tedious. Somehow, though, it suits the Mini's character and - because it's still not hugely loud and doesn't do a show-off wake-the-neighbours routine at start up from cold - it feels less anti-social overall.

Pocket-lintMini John Cooper Works - 12 copy

One factor we think contributes to the JCW's go-kart feel is the slick, smooth 6-speed manual gearbox. Mini launched the car with an autobox only option, reckoning more than half of buyers now go for this, but as of the end of last year, you get a manual gearbox as standard. With that autobox a £1,365 option, and definitely removing a level of fun factor from the car, we'd stick with the manual. It's no hardship.

So, pocket-rock status in-tact, you'll be wondering how much Mini want for the JCW. This model starts at £23,155. It's a lot of cash for a small car, but you're not buying size here - you're buying a lot of powertrain hardware, a high-quality object and a premium experience.

Nowhere is this more apparent than when you step into the interior, which - like all the new Minis we've tested - feels very high quality, particularly in the areas you regularly touch, such as the steering wheel. Materials and finish are up at Audi levels, and the bucket seats, finished in a fetching red and grey Alcantara for the JCW, really set things apart from the other, less powerful Minis.

Pocket-lintMini John Cooper Works - 5 copy

You can get nice and low behind the wheel, which sits in a snug but not tight driving position. It's those seats that hug you tight in the corners and are very comfortable over long distances.

However, the boot space is still weeny, but you can get a couple of adults in the back of a Mini these days. And if you need more space, Mini offer JCW versions of the 5-door Mini, Clubman and Countryman.

The bigger question is how to keep the purchase price in the £20K bracket. Like all Minis, it's worryingly easy to drop the best part of £10K on options on the JCW - and indeed our test car had been through just such a process.

So max out to your heart's content, but if you want the performance but don't fancy the queasy price tag, what are the must-haves? The good news is that engine, gearbox and most powertrain and chassis-related bits that make the JCW a hoot are standard. The key option our car had was the aforementioned adaptive dampers, at £240.

White or red paint is free, and suits the car great, but our car's 18-inch wheels are a £740 option. Don't worry if you don't fancy them – we're sure the ride on 17-inch standard wheels would be nicer still. The racing seats are standard, and you can choose how much you want to spend on trimming them in different colours and leather finishes.

One option to add (as ever with any Mini) is the Chili Pack. It's a chunky £2,400 option, but the good news for those financing their Mini is that it helps residual value, so should only add £30/month or so to the typical deal. It includes the bigger wheels, and the leather/Alcantara seat trim, plus on-board computer, climate control, a lighting pack, auto lights and wipers, and extended stowage.

Pocket-lintMini John Cooper Works - 29 copy

Many will want to add the Media pack too (£1,400), which brings a widescreen sat nav system (from BMW, which works very well), enhanced Bluetooth (streaming, multiple phone connections), and connected services. You can max this outwith the £2,400 tech pack and get all this plus a Harman Kardon sound system, reversing camera and a head up display (HUD), too.

Stick to Chili and Media pack, and you're looking at a £26,955 Mini John Cooper Works. Yep, it's not cheap, but then you drive the car and it feels worth it.

Verdict

Mini's proposition asks you to make a fundamental decision: are you happy disconnecting the price you pay for a car, with how physically big it is? If you're of the old school view that the fat end of £30K really ought to buy you a very sizeable car that seats five and takes their luggage in comfort, then we suspect you've stopped reading well before now.

Because Mini offers BMW technology in a small package that's beautifully appointed, but not exactly cheap. With the John Cooper Works version, you get all this plus performance to embarrass much bigger cars, which can always put a smile on your face and feels perfectly optimised for British roads.

Is this more fun than a much cheaper Ford Fiesta ST? Does it offer as much value and performance as a far bigger VW Golf R? The objective answer - looking at on-paper figures - is no. And if you're bothered about the ultimate cost of the car in purchase price or monthly finance deal - or being able to transport you and three friends or family around - then the Mini is probably not the answer either. But despite this, the JCW has terrific appeal - and we suspect many will love it. It's a more bespoke, special-feeling object than any city car-sized Fiesta, Clio or such. Yet it's even more fun. And it feels much less like a normal, bland-box than a Golf, too.

We suspect John Cooper (senior) would have been very proud indeed at the way BMW is continuing his legacy. After our week with with the Mini JCW, we're still smiling about - and missing - the presence of this mini yet mighty car on the driveway.