It was 15 years later that I first drove a D-type — the ex-Duncan Hamilton long-nose, 2 CPG. At that time it belonged to Anthony Bamford, who now has among so many other things one of the 1957 Ecurie Ecosse cars. It was everything I had expected: the hard, booming exhaust note was unchanged from my memories of the spectators' enclosure at Madgwick.

The D-type is such a part of motor racing history that one tends to forget what a revolutionary car it was 25 years ago. That marvellous shape, the work of the late Malcolm Sayer, was designed for one thing: speed on the Mulsanne Straight. The tail-fin, to give straight-line stability, was there for the same purpose. If the basic shape had not played so large a role in the styling of the now so familiar E-type, the D would still seem positively futuristic.

And not only was the D-type fast: it was strong (that monocoque construction), reliable (the unburstable XK twin-cam six), and endowed with excellent handling, roadholding and particularly braking — thanks to the recently-developed Dunlop disc brakes which had appeared victoriously on the C-types in 1953. If the lighter, more agile Aston Martins with their De Dion rear ends were a match for them on the tighter British tracks, at the Sarthe circuit the Jaguars were unbeatable.

Four years ago, with the prices of D-types reaching ever dizzier heights, two separate companies announced almost simultaneously that they were prepared to build replicas. One, Deetype Replicas Ltd, is run by Bryan Wingfield from a base near Chelmsford: I had a brief go in their first example just after it had been completed, and was highly impressed by its finish and accuracy. The other is Lynx Engineering, run by Roger Ludgate and Guy Black. They have impeccable credentials, because their company has been rebuilding and restoring C-types and D-types for some time. DCM, the TR Centre in Kensington, are now sole agents for the Lynx, and it was their Richard Kwolek who offered me their brand new demonstrator for a weekend.

But my weekend started badly. The car was delivered to my office on Friday afternoon: unable to resist, and ignoring the extraordinary fact that it seemed to be getting dark at 3pm, I set off round the block — and immediately got caught in a torrential cloudburst. Crouching behind the tiny screen, my Friday suit sopping and my spectacles opaque, I weaved through the traffic as fast as I dared towards an underground car park. The brakes didn't seem to be working very much. My anxious prods at the throttle produced wheelspin in any gear and snaking slides. The lovely leather seats had puddles forming on them. Hailstones had inserted themselves between the back of my neck and my shirt-collar and were trickling down my spine.

Once in the haven of the car park, I wrung out my suit and used it to mop up the Lynx's upholstery. Then I stood back to admire the construction and finish of this facsimile D-type. It really is quite beautifully made.

The appearance is absolutely right: that compact, crouching, rounded look, the deep glossy dark green paint, the louvres, the rivets, the sweep of the tail-fin. Under the bonnet the cam covers of the familiar straight-six are mirror polished, like the alloy header tank and the trumpets of the row of twin-choke Webers. The dry-sump tank is missing (although Lynx will fit a dummy if required which does duty as a neat tool-kit) and the exhaust manifolding is standard E- type to allow legroom for the passenger, although fabricated D-type manifolding is available. But from the outside it was only this car's H registration, a legacy of the E-type which was plundered to build it, that gave the game away.

Of course the Lynx is not, nor is it intended to be, a perfect replica in every way — although as far as the exterior is concerned, that's just what it is. Under the skin there is central monocoque tub, just as on a real D-type, but the front subframe is adapted from an E-type, as is the torsion bar front suspension. At the rear, instead of the D-type's rigid axle and trailing arms, there is the familiar E-type coilspring setup, except that one spring is removed from each side to compensate for the much lighter weight of the Lynx. The peg-drive alloy wheels, specially made for the car, look just right — but they have steel rims and are I5ins diameter, which helps tyre availability. But the alloy body is a perfect copy in every detail of the 1957 long- nose D, and is an absolute masterpiece of the panel-beater's art.

Sitting down inside the deep cockpit I found the fixed seat too vertical, too wide and too near the wheel for my liking: but of course all these details can be suited to the purchaser's individual specification. The seats and headrest are beautifully trimmed in best leather and there is quality carpeting, which Rolt and Hamilton never enjoyed at Le Mans. Original D-types varied in dash layout, but this Lynx had large speedometer and rev-counter, oil pressure gauge and water temperature gauge on the crackle-black dash. The steering wheel obscured both rev-counter and speedometer, but as both were wildly inaccurate on this car that was no hardship. The horn button was by the driver's right knee, exactly where it was on some D-types: not all, because no two D-types were ever quite alike, just to make the forger's job more difficult. Other controls were confined to winkers and lights, plus the switch for the non-thermostatic electric cooling fan.

Punch the starter button and the engine idles at once inches away, the big Webers hissing. My car had a recently rebuilt and near-standard 4.2 E-type engine; it was rather tight and the Webers needed synchronising. But with 250bhp to move around less than a ton in weight, the performance was electrifying. It was lumpy at low revs and spat back through the Webers at small throttle openings, but the Jaguar flexibility and torque were still there, and once over what I guessed to be about 3000rpm the car really got into its stride. The later-type all-synchro Jaguar box needed a firm hand but changes were rapid enough when the revs were right, and the acceleration in third up to the change into top at around 120mph was breathtaking. Hidden underneath for reasons of legality were E-type front silencer boxes, so the real D-type bark wasn't quite there, and cruising at small throttle openings at 80 or 90mph the car was quite quiet; but drop into second leaving a roundabout and floor the throttle, and you're powering away from Tertre Rouge in a great surge of power and on down the Mulsanne Straight. Every transport cafe on the A30 became Les Hunaudieres in my mind's eye . .

To put the performance in perspective, Roger Ludgate's own Lynx, with 50,000 hard road miles on the clock and a mildly-tweaked but healthy 3.8 engine, was tested by another magazine under power conditions and achieved 0 to 60mph in 5.6secs and 0 to 100 in 13.9secs — faster than a Porsche turbo or a Ferrari Boxer. If I could afford a Lynx, I'd give the engine to Ron Beatty of Forward Engineering and get it perfectly set up, and I'd run the full D-type exhaust system because I'd be rich enough to pay the fines.

I'd also make sure the brakes were sorted out. With E-type discs to stop a much lighter car, my Lynx should have had faultless braking but, just before I took the car over from DCM, twin servos had been rather hastily fitted and the system obviously had some air in it, because the pedal was spongy and needed a hefty shove actually to slow the car.

The steering — remember this was a newly assembled car with less than 500 miles on the clock — had a slight stickiness but was direct and beautifully responsive. On the correct Dunlop R5 tyres the ride was harsh at low speeds and the Lynx 'nibbled' a bit at white lines, but on long, fast corners — given a reasonably smooth surface — it felt rock-steady. The top of the screen, an authentic 1957 Appendix C height, almost coincided with my eye level, but it was best to sit up straight and look over it. For much of my 300-mile weekend I wore a full-face crash helmet, which was much more comfortable and also protected the face from insects and flying stones, although I did feel rather conspicuous (and anachronistic) at the wheel in my Bell with smoked visor! And at speeds of over 120mph the wind seemed to be trying to tear the helmet off my head. Perhaps the earlier-type screen which wrapped round to the headrest would be better: at 175mph on the Mulsanne Straight for lap after lap it must have been very tiring.

When you have a nice car for the weekend you need an appropriate audience to show it off to. Mercifully the weather for the rest of my ownership was perfect, and as I found myself in Somerset on the Saturday afternoon I decided to drop in for 10 minutes on my good friend Rob Walker at his beautiful country house (whose grounds also encompass a castle and most of the surrounding village). The 10 minutes stretched to a couple of hours because, after some fascinating reminiscences from Rob, he decided to get his gullwing 300SL Mercedes-Benz out of the garage.

This was not the original ROB 2: the first 300SL to wear that number was the first one in the country in 1954, and it was followed by a lightweight gullwing, then a convertible. Rob bought his fourth 300SL in the 1960s from Dick Wilkins, with whom he used jointly to enter the 250GT Ferrari in which Stirling Moss won his seventh TT. Even now it has done only 18,000 miles. Most of Rob's cars are not kept at his home, but the Mercedes had been sitting untouched in the garage for eight months. It started first time on the button, and we went out on a circuit of fast, narrow Somerset lanes of which Rob obviously knew every inch from countless previous demonstrations and trial runs. Brave chap, he let me drive the 300SL with himself as passenger, while his son followed in the Lynx.

This story isn't about the 300SL, so I will just say (having never driven one before) that for a 3-litre road car a quarter of a century old it was astonishingly fast, with a beautiful gearbox and heavy, precise steering — and that all the stories about the 300SL's swing-axle rear suspension and its awe-inspiring oversteer are true!

Beside the Mercedes, the Lynx looked perfectly in period, and Rob agreed with me that the quality of execution and attention to detail were superb. But of course all this workmanship, and the hundreds of hours it involves, does not come cheap. If you happen to have an E-type ripe for conversion, and if you have all the facilities to put a Lynx together properly, you can start with a basic kit from Lynx for less than £12,000.

But that does not include a number of 'extras' that most of us would regard as essential. Like the correct peg-drive wheels, rather than steel wheels on splined E-type hubs — they are £394 extra. Interior leather trim and carpeting come to almost £400. The right D-type steering wheel: one that is very nearly right is £15 off the shelf, but exactly the right one is made up by hand and costs £165. For over £2000 you can have a dry-sump engine, if you think you are going to corner hard enough to have oil surge problems. And a Lynx to correct XKSS specification — no headrest, but screen, wipers, hood, bumpers and luggage grid — is £3850 extra.