It's not often we test a racecar, but the road-going version of the new Radical SR4 Clubsport won't be ready for a couple of months, and to be honest we couldn't wait that long. We know from the SR3 that the differences in the driving experience between the racer and the road car amount to nothing more than a gentle softening of the performance edges, so this should tell us what to expect by the time we get our hands on the road-going SR4 at our annual Trackday Car of the Year event. We have high expectations for it too, as the SR3 is the reigning TCOTY champ. The SR4 is not a replacement for the SR3, though, more a development of the original Radical, the Clubsport, a car that has proved hugely popular on the racing scene since its introduction in 1998.

The SR4 is fitted with a 1200cc Kawasaki bike engine that transmits 190bhp (up 5bhp) via the simple but effective Clubsport chain drive and Quaife LSD combo (with reverse), but the chassis has been redesigned to make room for a passenger and, of course, the aerodynamics are all new.

Looking like a Le Mans racer in miniature, the racing influence is more than skin deep with positive downforce and air ducted into side-mounted radiators. The car's detailing, from the carbon dash to the polished aluminium exhaust, is first rate and the level of finish remarkable for a racer. The suspension layout is the same double-wishbone all-round with rising rate anti-roll bars as found on the SR3.

Once aboard you sit low and reclined in the cockpit, squeezed by wide harnesses into deep moulded seats. We've no time to sit here admiring the view though; it's a bright early spring day and we're at Brands Hatch on the short Indy loop, the ideal venue and conditions for testing this club racer.

Flick the ignition and fuel toggle switches, thumb the starter button, prod the throttle and the ZZR bike unit yelps into life and settles to a fizzing, buzzy idle. Snick the gear forward into first, feed-in the clutch and ease down the pitlane.

The first few laps are gentle to give the cold Matador slicks time to warm to the task in hand. You're forgiven for not being familiar with this Slovakian tyre producer; Matador has been working with Radical over the winter and designed these slicks specifically for the SR4. It soon becomes apparent that the work has paid dividends. These tyres are brilliantly in-tune with the chassis and the good news is that Matador is working on road-legal versions too.

As the laps pass the speed builds and the driving experience intensifies. The engine sounds superb, screaming away at 11,000rpm behind your head and with just 450kg to move it provides plenty of shove too. But it is the braking, grip and high-speed cornering that make the real impression.

If you have only ever driven regular sports cars - Ferraris, Porsches, Caterhams and any other supercars you care to mention - you will never have experienced anything like this. The SR4 responds instantly to every tiny input, but does so without ever feeling nervous or twitchy. Brush the brakes and it sheds speed in a serious hurry, turn-in and the nose dives hard towards the apex with incredible accuracy, and although the aerodynamics pin the car into the tarmac, it is still possible to massage your line with the throttle. High-speed corners such as Surtees and the mighty Paddock Hill Bend are an incredible assault on the senses since you can carry ten per cent more speed than you thought possible. Getting into the zone where the tyres are working hard requires real commitment, not because it feels unsafe but simply because it's outside any experience you might be used to. The rewards in terms of driver satisfaction are massive. Adrenalin junkies will get a massive fix from the SR4.

We know trackday driving isn't solely about lap times but they still give you a good guide to overall performance and the SR4 lapped Brands consistently in the low 47sec bracket - quite some achievement when you consider that Yvan Muller's BTCC lap record stands at 49.2! The SR3 has been described in this magazine as 'nothing short of awesome'. As a trackday warrior, the SR4 threatens to be even better.