The Jaguar F-type may be the first reinterpretation of the E-type theme to make it into public view, but it is not the first. Somewhere down a long lane deep in the heart of East Sussex, a company called Eagle has created another, somewhat different take on the theme.

It’s called the Speedster and if you want one, it’ll cost around £600,000, assuming you can persuade Eagle to make you one. The first Speedster is already in America and you’re looking at the second. The third is almost complete and numbers four, five and six are in build. After that, there are no plans to make any more. “Got to keep it exclusive,” grins Paul Brace, Eagle’s general manager and the man who styled and engineered the extraordinary slice of automotive art now quietly warming its engine beside the test track.

You will know Eagle, or at least you should. Led by self-confessed E-type obsessive Henry Pearman, these are the people who for more than 20 years have been taking E-types and restoring them so extensively that quite often ‘as new’ condition is not the objective but the starting point.

All manner of modifications are available, but if you simply take your old E to them and ask them to slip their injected 4.7-litre engine under its elegant bonnet, or fit their bespoke five-speed gearbox, your business will be ever so politely turned away. “We don’t, or at least won’t do partial restorations,” says Brace. “We’ve seen too many cars that look all right but turn out to have all sorts of issues under the skin. If a car is to call itself an Eagle, we need to have been through it from end to end.”

So it’s all or nothing. It also explains how, if you want to buy an E-type and are brave, you can pay as little as £15,000 for a running car, but if you want a fully prepared Eagle with all of the good bits included, you’ll be looking at a bill for something the far side of £250,000. Even cars that appear perfect are taken back to their bare components before being painstakingly rebuilt.

The Speedster, however, is something else again. It is based on an original E-type – a 1965 Series 1 4.2-litre roadster in the case of the car you see here – but where it differs even from other Eagle E-types is in that astonishing body, which is not only completely restyled but also made entirely from aluminium.

The reason is that the Speedster was created as an homage to the original dozen lightweight E-types built by the factory in 1963, any one of which would sell today for money that would make even the Speedster look cheap. Like the Lightweights, and unlike all normal E-types, the Speedster has an aluminium body and engine with fuel injection and a five-speed ’box. This is why the fully trimmed Speedster weighs just 1008kg – less than the lightest Ford Fiesta on sale.

When you look at these pictures, I fear it might be hard to appreciate the impact the car has in the flesh. For a start, it’s tiny. It looks impossibly long, but in fact it is both shorter and narrower by far than a Ford Focus, which just goes to show you how much cars have grown over the years. As for its height, think of the lowest of the low, such as a Lotus Elise, and then think lower still. The Ford GT40 was so astonishingly low that it got its name from its height in inches, but the Speedster is lower even than that, with the top of that swept back, cut-down screen sitting just 1000mm (that’s 39.4 inches) from the ground.

Then there is the finish of the thing. Normally Eagle does all its work in house, but the job of creating the Speedster’s unique body was given to expert ally basher RS Panels in the Midlands, before Eagle applied possibly the best paint finish I’ve seen on a car wearing a number plate. It’s not actually black, but the deepest, darkest red imaginable. When hit by natural sunlight, it looks so rich and exotic that it can make a stone cold concrete test track feel like the Riviera in mid-summer.

The idea of taking the E-type design – only the second in automotive history, after a 1946 Cisitalia, to earn a place on permanent exhibition in the New York Museum of Modern Art – and modernising it would be enough to give most car stylists palpitations, but Eagle’s success can’t be questioned. By lowering the screen and floorpan and adding deeper sills, the car looks instantly more purposeful and masculine, while extending the track so the wheels fill those subtly flared arches removes perhaps the only flaw in the original’s design. I’d not have chosen such shiny wheels with such large spinners, but it’s easy to carp without having a clue as to what to put in their place while staying true to the spirit of the car. And I love that swept-up back with its big haunches and fat central pipes.

Inside, it’s the E-type you hope Jaguar would have given you had it not needed to design the car down to a price. The architecture is unchanged, with the same simple, elegant yet effective dash and the inimitable central sweep of dials and switches. But the seats are bespoke (and heated) and the upholstery is as good as it has to be in a car costing as much as a mansion in some parts of the land.

The Speedster is warm now. Pearman and Brace are adamant that, despite the age of the underpinnings, all Eagles should run and be able to be treated like modern cars, and are built with this in mind. The engine is bored and stroked out to 4.7 litres but develops just 310bhp on standard cams. Racing E-types now have far more power from just 3.8 litres, and there’s no doubt that if they so wanted, the Speedster could have in excess of 400bhp. But it wouldn’t sit and idle so evenly or provide such a magnificently wide spread of torque, which peaks at a gutsy 340lb ft at 3600rpm.

If you are at all familiar with the E-type breed, you could climb in and know this car blindfolded. This is remarkable because the driving position has dropped, the seat is different and your hands grip a small diameter Nardi steering wheel about which even Brace is having second thoughts. Of course, because it’s an entirely bespoke product, you can have whatever you like. I’d stick with the large original Jaguar item.

As in any E-type, the pedals seem closer than appears right, but the car takes all 6ft 4in of me and my size 11s with ease. In my dreams, and were this car mine, I’d do something about the screen height, because while those who queued up for passenger laps of the track all remarked on the car’s impressive wind management, I recall mainly a super-cooled forehead.

But I remember more just how easy this car is to drive. Again, Eagle could so easily have made a mess of this, modernising the Speedster so much that no element of E-type remained. In fact, it feels like nothing less than the car Jaguar would have provided had it the time, money and technology at its disposal.

The gearbox, designed around a Ford casing to Eagle’s own specification, feels like a later E-type ’box (the Moss ’boxes in the first cars were slow and obstructive) but with one more ratio. As for the ratios themselves, it’s your car and you can have any you choose. The suspension is fundamentally E-type, but with modern dampers and modified geometry featuring increased negative camber to make the car work on modern radial tyres. It also happens to make the car look very cool. Braking is by fat AP Racing ventilated discs, with those at the back retaining their inboard positioning.

The first time you squeeze the throttle, it’s difficult not to laugh. You’re in third gear with only a couple of thousand revs on the clock and you’re not expecting much more than a hardening of the exhaust note and a gentle increase in tempo. Instead, the Speedster sits down at the back, sniffs the air at the front and charges. By modern standards, 310bhp may not sound like much, but what modern car with that power has only a tonne to tow? In terms of power to weight, it’s just a sniff behind a Mercedes-Benz SLS Roadster or new Aston Martin Vanquish.

The noise is pure E-type: deep, melodious, inimitably old English twin-cam straight six, quieter than I’d expected but still loud enough to make you proud to be British. The red line is set at 5000rpm, which I reckon is actually 500rpm short of what an old E-type will safely pull, but as peak power comes at just 4700rpm in this long-stroke motor, there’s never any sense of your enjoyment being spoiled. Just flick the lever into another gear and let the fun commence again. The speed at which 120mph appears on the dial makes Eagle’s top speed estimate of over 160mph seem modest in the extreme.

But its even bigger charm lies in the way it handles. Eagle will, of course, set up a Speedster any way a customer chooses, but this one is surprisingly and pleasingly soft. There’s not much weight to transfer and with the E’s standard Power Lock limited-slip differential, traction is outstanding.

So despite its fat modern tyres and modified suspension, it still feels like an E when you angle it into a corner. It doesn’t flick on to your new line like a modern sports car; instead, it rolls gently, information flooding through that wood-rimmed wheel. You think it wants to understeer, because that’s what it does on a balanced throttle, but that’s not how you drive cars like this. Instead, what it likes is a little lift just to get the weight on its nose, then not the aggressive boot of power you need to unstick a modern, but a steady stream of torque to the rear wheels to start them gently slipping. And then it will drift and drift until you’ve convinced yourself you really are Roy Salvadori in an original Lightweight once more.

Whether you or I think the Speedster is worth £600,000 really is an irrelevance when the total production run of six is already spoken for. Those who matter clearly think it is. The thought that lingers longer in my mind is how brave it was to think the E could be modernised without being turned into some ghastly pastiche, that one of fewer than 10 cars ever built to deserve truly the description of ‘icon’ could be so altered while leaving its essential character intact.

And another thing: during our day at the track, the Speedster did lap after lap on or over the limit, then slid back and forth through the same corner a dozen times or more to create appropriate imagery for the camera. And not once did it get hot, fail to start, creak, groan, whine or complain at the treatment. In this regard, it behaved precisely as you’d hope and expect a brand new Jaguar to behave. In short, it provided all the pleasure, far more raw ability and none of the pain of owning one of the world’s greatest sporting cars. The only pity is I can’t afford one.