EVERY now and again, you’ll get in a car, take it for a drive and it surprises you. You find it’s a wolf in sheep’s clothing, a surprise thrill. Us petrolheads call them sleepers.

The Abarth 595 Competizione is not quite so subtle. You only have to look at the exterior to figure this out. It looks like the lowly Fiat 500 upon which it’s based has suffered an awful allergic reaction to something. It has extra bulges and swooshes and spoilers and it makes a frank visual confession of its purpose.

And then you sit in it. It has a stubby metal gear nob, a suede-rimmed steering wheel, a turbo-boost gauge and deep, figure-hugging carbon fibre seats.

And if you’re still gullible enough to think you’re in for little more than a sedate pootle then you’ll get quite a shock when you start the engine. It has something called a Record Monza dual-mode exhaust which, let’s not beat about the bush, is ridiculously loud.

Abarth’s reworkings of the Fiat 500 are nothing new. In fact, the firm fiddled around with the diminutive original version in the 1970s, but they’ve been playing with the current version for nearly a decade.

So let’s just say they know what to do. And, rather than get all complacent and just stick a few trinkets on, they’re now eking huge power outputs out of the small engines and cramming in the sort of sporty kit you’d find in six-figure supercars.

For example, the engine might only be a 1.4-litre, but its turbo works so hard they’ve managed to squeeze 180bhp out of it. And all that power in a car this small is an obvious recipe for fun.

It means the 595 Competitizione is good for 0-60 in 6.7 seconds and, wielding such a powerful tool with such a short wheelbase around country lanes is, obviously, an absolute hoot.

I would never tire of sprinting out of bends with the sport mode switched on, everything turned up a notch, and with the window fully wound down to hear the rorty exhaust hitting the high notes.

While there’s obviously plenty of fun to be had, the problem with small pocket-rockets is often a lack of practicality. True, the big sports seats do hamper rear-seat space, but the 500’s decent boot is still unhindered.

At a shade under £21,000 in basic spec it’s certainly a pricy hot-hatch when compared to the likes of Ford’s Fiesta ST and Peugeot’s 208 GTi, but neither of those cars have the character of the 595. It feels alive, angry and constantly eager.

The ride is, obviously, compromised, as the Competitizione is set up for B-road blasts rather than pothole-riddled town centres The lack of cushioning on the seats does little to help.

And I don’t want it to sound like I’m not a fan of those lovely seats, because I am, but they’re so substantial that it’s basically impossible to recline them with the door closed – the wheel is too close to the door.

The gear-change is a tad disappointing too. I would have liked a snappier gearbox, with shorter ratios to match the frantic engine and boisterous exhaust note. The 500’s lofty driving position, which is carried over, doesn’t suit me much, either, although I know that won’t bother some people.

But while it’s not perfect, it’s hard to pick fault with a car that will only be bought by people who care very little about whether they have to open the door to recline the seat, or whether the booming exhaust will become tiresome on the motorway.

This is a car designed to look good, go like stink, entertain in the bends, and shout very loudly about how sporty and aggressive it is. It fulfils its brief perfectly.

I’ve always had a soft spot for the Fiat 500, it’s cute and fun and practical. But, although most of its parts are shared with the Abarth, the 595 Competitzione couldn’t be more different.

The 500 is like a sweet librarian in a hand-knitted sweater with a picture of a kitten on it – while the 595 Competizione is like a night-club bouncer baying for blood because you’ve just insulted his mother.

It is bonkers in a bullish, raw-edged and wonderful way and, at least in terms of thrills per cm, it’s pretty much un-matched in the world of hot hatches.