This is the stunning Eagle Low Drag GT

Imagine having the E-type in your back catalogue. How do you top that? Ferrari may have created a greater number of masterpieces, but even ‘Il Commendatore' himself knew when he was beaten. "The most beautiful car ever made," was his verdict on the Jaguar. Malcolm Sayer, the company's aerodynamicist and designer, reckoned it was drawn according to strict mathematical principles, which rather debunks the romance of the creative process. Whatever, the E-type was the first car to be selected to appear in New York's Museum of Modern Art.

Heritage is huge business, but even Jaguar must occasionally want the E-type to, you know, clear off for a bit. Not least because the F Coupe is the most explicit successor they've created since the original passed away in 1974. Can't it enjoy its moment in the sun?

Pictures: Rowan Horncastle

This feature first appeared in Top Gear magazine

Click here for desktop-worthy wallpapers of the reborn E-type

That's a fleeting commodity at the TopGear test track today, but the F-Type Coupe is a magnetic, mesmeric presence, even as the clouds swiftly gather above to close its solar window of opportunity. It's also a startling car to drive, as Paul Horrell has just explained - rampantly fast, friendly if you want it to be, bad to the bone if you don't. Maybe this is what the E-type would have naturally morphed into 40 years later.

Or maybe that's the Eagle Low Drag GT. It's difficult to know where to start with this thing. There's an anvil-shaped cloud right overhead as we watch this silvery capsule arrive alongside, standing water sluicing off its fat back tyres. Its paintwork is like liquid mercury, and rarely has the E-type's fuselage looked more sublime. The finish is a complex multi-layered one, designed to exemplify this particular car's unique aluminium body. But it also has the effect of exaggerating every globule of water that's sitting on it, so that it glistens with extra intensity.

It would be ethereal - alien, even - if it weren't for the noise. At idle, it thrums with the innate harmonic purity only a classic twin-cam six-cylinder unit can generate. But two minutes ago, it was roaring along the runway like that other soul-stirring British classic, the Spitfire, emitting a sound so ripe it tingles your spine and creates a Doppler effect you could get lost in.

But wait. This is TopGear, not Classic Car & Sports Jacket magazine. Do we do old cars? We do when they're like this. In fact, the Eagle Low Drag GT arguably isn't an old car at all. Eagle has been in the E-type business for 31 years, and still buys and sells Es out of its premises in East Sussex. From fettling original cars, the guys began to offer a programme of upgrades, identifying the E's weak spots - numerous, on account of it being a classic British sports car - and doing the development work that Jaguar would probably have done if it had fallen through a hole in the space-time continuum and money were no object. At some point, these ceased being restorations and became remanufactured cars. Better than new.

Following its much-loved Speedster, and with 32 cars delivered and a further three orders on the books (including one from Simon Cowell), Eagle turned its attention to a reincarnation of the most fabled of all E-types, the Low Drag Coupe. Sayer actually made one in 1960 as a putative racing car, but as Jaguar could sell every E it made, it didn't need the hassle or expense of a racing programme (against rivals like Ferrari's 250 GTO and LM and Ford GT40, among others).

In 1963 and '64, a couple of privateers did end up racing converted cars - tragically in the shape of the ‘Lindner/Nocker' E-type - but mostly it remains a shapely footnote in the history books. When Eagle embarked on a reimagining of the Low Drag, an existing client took one look at the work-in-progress and said, "Build it." Now, 7,000 labour-intensive hours and £695,000 later, here it sits.

A donor car, retrieved from California with the original suspension intact, technically underpins it, but in reality everything is new or substantially improved. The body is all-aluminium (E-types were steel, apart from 12 lightweight roadsters), and there's a lower floorpan and an extra two inches in the wheelbase. The glazing is made just for the Low Drag, flush fitting and bonded, the chromework expensively satin-finished. There is proper recirculating aircon inside rather than an asthmatic ventilation system, bespoke seats with proper bolsters and Alcantara headlining. The door hinges are sculpted ingots, the sun visors slivers of blue Perspex, the dash architecture as per the original but with extra labels and exceptional quality.

But the real juice is under that famously priapic bonnet. Here you'll find a gorgeous inline six-cylinder, bored and stroked to 4.7 litres and 346bhp, with bespoke internals, including a new crankshaft and oversized valve gear. Purists might get a touch huffy at the sight of the carbon-fibre topped plenum chamber, and triple SU carburettors are possibly a more romantic notion than this car's fuel injection, even if they're not as user-friendly.

But it's pure mechanical eye candy. Original E-types featured a tricky non-synchro Moss four-speed gearbox; Eagle has developed its own alloy casing and five-speed 'box. There's also an aluminium limited-slip diff, and the suspension has been heavily modified, with an adjustable front anti-roll bar, fully adjustable Öhlins dampers and unique spring rates. AP Racing supplies the brakes - 315mm ventilated discs at the front, 280mm at the rear, with four-pot calipers - and the Low Drag GT's 16in magnesium wheels wear 235/60 Vredestein rubber at the rear (an unusual spec, and hard to find, according to Eagle's technical director, Paul Brace).

It also weighs just 1,038kg. That, plus its frightening cost, its rarity and the fact that it belongs to someone else who loves it more than life itself, suggests that kid gloves are the order of the day. Besides which, there isn't a dry patch of tarmac to be found within 100 miles of here right now.

But the Low Drag GT is immediately brilliant. First of all, I can fit into it, and I can also get comfortable, something I've never managed in the E-types I've driven before. The wood-rimmed Nardi wheel is as thin and lovely as a Sixties supermodel, the pillars slender. The clutch is weighty, and first gear needs a firm hand, but, after that, the Eagle is precision itself off the line and beyond. Most classic cars - the good ones, at least - have a linearity and lucidity that instantly rewires your ideas about steering feel and what handling really means.

This thing is fantastically communicative without being in-your-face. You can feel the meshing of cogs as you change gear, and as slow as it might be, or as out of step with the modern, high-performance dual-clutch semi-auto paradigm, it's way more satisfying. Not least because, on the road, you have to think that little bit harder about everything you're doing, and you get the reward you're looking for at a less lunatic velocity.

The Low Drag's unexpected civility encourages you to stretch out of your comfort zone, though. Remember, there are puddles of water all over the place. But as you rev it out towards its 5,000rpm red line, there's that sound again, a honeyed roar rather than a howl. All 360 torques are on hand at just 3,600rpm, so it surges and surfs along. It stays stable as the speed rises, is seriously rapid (0-60mph in well under five seconds), but pulls up with little fuss. We even get to have some fun, and discover a chassis that's surprisingly cultured and adjustable (literally: those Öhlins can be set up according to preference).

It doesn't take much to get it sliding, and it's not difficult to balance it on the throttle once you're dialled into it. Easier, in fact, than trying the same malarkey in the F Coupe, which can be surprisingly spiky as you rein it back in.

The Low Drag GT has the kick of a good malt whisky. It feels like something that's been 50 years in the making, that blends the character and complexity of an old legend with the artistry and intelligence that only come after years of hard graft and head-scratching. Perhaps you'd expect it to be good after all this time. But actually it's a lot better than that.