polar moment of inertia, he explains, you get a maximum theoretical tip-over limit of 3.27 lateral g, which is greater than the tyres can generate, so it will slide rather than tip over.    Also, the very low polar moment of inertia yields quick transient responses to steering input. Under hard braking, around 33 per cent of the vehicle weight is on each tyre, with approximately 66 per cent of the weight on the rear tyres, behind the centre of gravity, so the vehicle is in a dynamically stable condition; lock up and it wont spin.     If you want more of this sort of stuff, Bob is happy to oblige. He can bang on about yaw rates, axes of rotation,

stress loadings, weight transfer and static loadings until the hind legs have fallen off any number of donkeys.     However, the important thing is that, unlike many of the weld-it-and-hope chancers that have bodged together three-wheelers in the past, he has actually done his sums.     After all, fighter planes use the same layout as the Vig, he insists. The calculations of weight and balance Ive used are closer to aircraft design than traditional cars.     And, somehow, it works. With a bit of why didnt anybody think of this before? surprise, you can see what the means. It has a simple motorbike-type steering arrangement with no power

assistance, but it does have a turning circle a London taxi would kill for, and it goes round corners very quickly with a whiff of oversteer. You can actually unstick the rear tyres more easily than the front one strange, but true.     The top speed of this car, with the current 345bhp engine, is estimated at 215mph. Thats right, 215. With a proper race-spec engine developing 700bhp, it would crack the 250mph mark easily and keep going towards . . . well, God knows. I certainly dont, because it wasnt going to get anywhere near those figures with me in it.     But it feels highly possible. And at an estimated $125,000 (or more, if you

want a tuned engine), thats a lot of bang for your bucks. It makes a Ferrari F50 look slow and costly.     Bobs planning to start building Vigillantes to order just as soon as hes sorted out a bit of financial backing, and even has half an idea of reviving the TriVette concept using a Volkswagen Golf turbodiesel engine to achieve ludicrous economy.     Personally, I hope he starts making Vigillantes very soon. After, all, the idea of screaming around at 250mph in something thats a dead ringer for a de-winged jet fighter is irresistible. Robin meet the Batmobile.