Has British independent manufacturer Trident inadvertently built the greatest car ever?The Iceni may look like a traditional grand tourer with an elongated bonnet and sculptured rear, but turbodiesel power and the 8-speed automatic transmission cue engineering details which are at odds with its GT packaging.RebornOriginally Trident built low volume sport cars in the 1960s and 70s before succumbing to global recession and fuel price instability in the mid 1970s. After resurrecting the name in 1999, intense engineering and design developments at Trident followed. Consequently we have the new Iceni - production ready.Why should you care though? TVR has gone bust, and who cares about an odd looking British performance car with an ancient Norfolk tribal name? With claimed performance figures of 0-100km/h in four seconds; top speed around 320km/h and 4l/100km combined consumption the blend of performance and economy so uncanny as to be impossible to ignore.The dark art of torque multiplicationDon’t for a moment think it’s a diesel-electric hybrid; or weighs less than an Elise to enable such unfathomable performance figures. On the contrary, it weighs a substantial 1480kg and is powered by nothing less than the mainstay of American turbodiesel bakkie engines, the 6.6-litre Duramax V8. How on earth does it manage 3200km on a 100l tank of biodiesel then? Designer Phil Bevan says it’s all due to torque multiplication – and no, we don’t really know what he is on about either. What we do know is the 8-speed sequential automatic gearbox is the primary source of the Iceni's frugality.Special gearbox keeps it on the boilBuilt under license in America, the gearbox technical details are kept under wraps. Allegedly the design was so radical Bevan had to go across the pond to find a manufacturer, as engineering firms in the UK and Europe never though it could work.We do know diesel engines are most efficient when run at in their optimum rev range, at quite low revolutions, thereby reducing friction. “A diesel engine hammering down the M4 at 4 200r/min is not very efficient when with modification it could be doing it at 1 000r/min,” Bevan muses.In principle Bevan’s transmission has a continuously variable characteristic about it, keeping revs as low as possible and capitalising on the Iceni’s immense 1288Nm torque peak at only 1 800r/min."In F1, the optimum rev point is 18 000r/min; all gear changes occur at this figure. With the Iceni R it’s 3 500r/min, and our computer model shows at 90km/h the engine generates 402r/min equating to 3.9l/100km." Silverstone racetrack illustrates Bevan's the point. "On the main straight a Ferrari does 8 000r/min and it will scream past," he says. "When the Iceni goes past it is nearer to 3 000r/min, doing 225km/h, but it sounds like it is purring along at 80km/h.Turbodiesel bakkie engine - reallyQuite how Iceni engineers have managed to unearth 410kW and 1288Nm from an American bakkie engine which produces 272kW and 895Nm in standard trim is unclear. Perhaps more puzzling is how Iceni will happen upon an engine supply arrangement with GM – notorious for not considering low volume performance car manufacturers worthy of contractual engagement.Despite these question marks the Iceni seems a decidedly noble venture; running on diesel, consuming only 3.9l/100km at 90km/h (proven at the Millbrook test track recently), yet able to render epic performance when called upon.If one employs a performance-economy rule of thumb presupposing consumption doubles during enthusiastic driving, 7.8l/100km is still icecap preserving frugality for a 410kW car – or any car for that matter. The Iceni makes a Lotus Elise seem simply Veyronesque in terms of fuel economy. Who’s going to build it though?The interior is tastefully appointed in the great British GT tradition; though the odd bubble shaped oculight removable roof panels look like something from a Jetsons episode.Specification wants for nothing with ABS, traction control, satellite navigation, keyless entry and reversing camera’s ensuring customers are a world award from the Spartan British sports car experience which effectively killed off TVR.Trident have sunk nearly €2 500 000 of its own money in developing the Iceni to road-going specification; and needs an external capital injection to actually manufacture.If the performance figures ring as true as Bevan claims, Audi could do itself a huge favour and simply park the R8 V12 TDI in a museum, buy Trident instead and rebadge the Iceni.Bevan’s gearbox design seems revolutionary. Getrag, ZF and Borg-Warner might have to cancel all end of year leave for their design teams in order to catch up.Price to market figures of £75 000 are being bandied about. Though this may appear a lot of money you do get very low running costs not only from the ridiculous fuel economy, but service intervals are only every 160 000km.The British auto industry has a penchant for over promising and under delivering; we’ll reserve judgement until somebody from the motoring press corps does a trans-European journey in an Iceni. Still a noble idea though – no pun intended.