I know I’m not going to figure high on many lists of people to feel sorry for this week, but few things are better at raising my blood pressure than this sort of job. You’re asked to collect a colossally valuable supercar unrelated to any other in your experience and return it a few hours later having fully uncovered its dynamic capabilities and limitations while simultaneously completing a photoshoot without flying off the road once.With the Ascari, things were even worse. Make a mistake even in something as rare as a Ferrari Enzo and on the way to the job centre you can at least comfort yourself with the knowledge that you’ve reduced the world’s Enzo population by just a fraction of one per cent. Had I overstepped it in the Ascari KZ1, that figure would have been rather higher: one hundred per cent, in fact. This car is the personal transport of Ascari’s founder Klaas Zwart whose initials it bears and, a few dog-eared prototypes aside, is the only one currently in existence.Yet from the moment we rumbled out of the gates of Ascari’s Banbury factory to that when I returned the KZ1 in the requisite number of pieces, the only thing it failed to do was scare me in the slightest. For those unable to have fun without a near-death experience, this will come as a disappointment. But from where I was sitting, it was more akin to a triumph.You’ll appreciate why rather more when you learn what we’re dealing with here. The KZ1 is a £235,000 supercar, powered by a 500bhp, 5.0-litre BMW V8. This may seem a modest power output and little more than you’ll find in certain Mercedes estates these days, but a carbonfibre tub and carbon bodywork means it weighs just 1275kg, and there are VW Polos that weigh more than that.But if its slim build makes it stand out among a generation of really rather porky supercars (it’s over 200kg lighter than a Maserati MC12), everything else about the KZ1 seems to be taken straight from the supercar textbook. The engine is mounted longitudinally behind the driver. The gearbox is the same six-speed Cima unit you’ll find in a Pagani or Koenigsegg. Suspension naturally comprises a double wishbone per corner while the massive drilled brake discs are provided by AP Racing and clamped by six pistons at the front and four at the rear.I knew all this before I climbed aboard and, at that point, had found nothing to suggest why this car should be different and why it should deserve anyone’s £235,000 when so many better-looking supercars bearing names you’ve actually heard of are available for so much less.The interior gave some clue, however, as to why this car has been five years in the making since the first concept was shown in 2000. It has been beautifully designed and finished to a standard most supercar manufacturers would be proud to call their own. You can recognise the odd parts-bin button – the starter’s from a Vauxhall VX220 – and certain other controls have simply been reskinned, but the whole effect is classy and purposeful. The driving position provides no clutch rest and over-the-shoulder visibility is dire, but happily I have a second pair of eyes in the passenger seat, so I thumb the V8 into life, nudge the tall, thin alloy gearlever into first and set off to find out more.Do this job enough and, with some cars at least, you can tell they’re going to feel right even before you’ve started to drive fast. This level of steering feel, damping fluency and braking response doesn’t just happen: it can only be introduced by using expensive components tuned by gifted engineers with an innate understanding of what’s required and how to achieve it. Moreover the throttle response is superb and the ex-M5 engine still flexible in its heightened state of tune.But seriously spank it and, while the V8 responds immediately, it gives performance that’s merely very fast when, for this money, you might have been expecting feral. Ascari’s performance claims (0-60mph in 3.8sec, 0-100mph in 8.3sec) match those Ford makes for the GT to the tenth but, for whatever reason, the KZ1 seems to lack the GT’s capacity for straight-line savagery. It merely accrues speed very swiftly, the V8 staying smooth and civilised all the way to the 7250rpm limiter.Perhaps this would not be quite such an issue were it not so blindingly obvious that the Ascari could easily cope with at least another 100bhp. Make no mistake, the KZ1 is one of the finest-handling supercars of this or any generation. No Ferrari made today steers as well as this, no Porsche can match its superlative blend of ride and refinement. The fully adjustable suspension is quite softly sprung at the back to give exceptional traction, yet superb damping means first-class body control is a given, even on quite punishing surfaces taken at speed. Ultimately it does understeer notably, but this is simply how this car has been set up: if a customer wants a rather more challenging balance, the suspension can be configured to let you go as sideways as you like. As for the brakes, I’m not sure I’ve ever encountered a more reliable, consistent or better-feeling set of stoppers on any road car.This, then, is a car of real charm and ability. What I like most about the design is that no attempt has been made to make it a road-going racing car. It’s comfortable, seemingly well built and refined enough on the motorway to be used for hours on end, but when the time comes for fun, it truly delivers. With some luggage space and decent visibility, it would be a superlative long-distance GT with the ability to turn into a true supercar as soon as the roads allow.All I truly struggle with is the cost. It is well known that customers are less price-sensitive in the rarefied atmosphere of the six-figure price tag, but it cannot be ignored that cars like the Ferrari F430 and Ford GT offer similar performance, gorgeous styling and blue-blood pedigrees for around half the money. Ascari will be hoping the KZ1’s exclusivity (there will never be more than 50 built) will bridge that gap. I join them in that hope, for the Ascari is well conceived, developed and executed; for those reasons alone, it deserves to succeed. If it cost 50 grand less and had 100bhp more, it could even be a world-beater.