Okay, may as well get this one out of the way as soon as possible. I do not like the look of the new XJ. This is not because I thought the previous XJ was a beauty - though in fact I do, to the irritation (if he still remembers our conversation on the subject) of Jaguar's design chief Ian Callum, who thinks that car was a wonderful piece of work for the 1960s but is offended from his hat to his socks by the fact that the same basic shape was allowed to stay in production well into the 21st century.But even if the old car had never existed I would still consider the new one clumsy, and a great surprise from a man who has given us such delights as the current Jaguar XF and the Aston Martin DB7.Hopeless rear visibility, too. At one stage during this test I deliberately reversed the XJ into a space between two other cars. It took ages because I wasn't sure if I was about to collide with either of them. Callum has said (actually when talking about the XF) that "that's what parking sensors are for". Personally, I think that's what glass is for, and the XJ doesn't have enough of it.I don't think I'm going to get used to the XJ's outer appearance (though I promise I will confess if the day ever arrives). It may also take me some time to become comfortable with the interior design, which is sure to appal Jaguar traditionalists. The beautiful dials of the previous car are a thing of the past, replaced by a digital display with three "virtual" dials - the revcounter on the right, the speedometer in the middle and everything else on the left. The left dial is replaced as necessary with the display for the satellite navigation, which is more diagrammatic than realistic but is nevertheless a masterpiece of clarity.The major dials highlight the area around where the "needles" are pointing, which is a nice touch. What, after all, is the point of having your attention drawn to where 70mph and 3000rpm are if you're pootling along at 20mph and 1000rpm? The downside to the whole digital business is that the "needles" move in a slightly stuttery fashion which doesn't seem quite right for a luxury saloon.(Players of the ondes martenot prefer the original analogue version to the more recently developed digital instruments for a similar reason. If you haven't a clue what that sentence means, don't worry about it.)All the seats in the test car, and I dare say XJs in general, are magnificently comfortable, though there's less headroom than the size of the car might lead you to believe, and only just enough legroom in the front for a six foot three fellow like myself. Since this is the long-wheelbase XJ, rear legroom is epic, though not to a noticeably greater extent than in the old XJ LWB, the Lexus LS or - heavens to betsy - the Skoda Superb or Citroen C6. More of it, however, would probably be a waste.There is almost nothing to be said against the 275bhp three-litre V6 turbo diesel engine which is surely going to be the most popular among XJ customers. One slight niggle is that you could feel its beat thrumming through the body at tickover, but since the car I was driving was a pre-production version it may not have been representative.You might want, but you certainly don't need, more than 275bhp in an XJ, and its ability to perform at any speed from just above stalling to just below the revlimiter - and to do it so quietly that an unaware passenger might never guess what fuel it used - makes it a worthy rival to the excellent similarly-sized diesels produced by Audi and BMW.The 0-62mph time is 6.4 seconds and the combined fuel economy is 39.2mpg. These are remarkable figures for a car as large as the XJ, and they are explained by the fact that Jaguar uses, as it did for the previous car, aluminium construction. The weight benefit is substantial; the three-litre diesel long-wheelbase BMW 7-Series, for example, is nearly 170kg heavier (probably about as much as the engine weighs) despite being slightly shorter.This relative lack of weight has a big effect on the XJ's road behaviour. It has been designed to feel similar to the XK and XF, and indeed it does - all the major controls operate smoothly and precisely. Better still, it is nearly as nimble, to the extent that on one occasion I was able to stay on the left-hand side of a twisty country road while easily keeping up with a Vauxhall Astra whose driver was crossing the central white lines at every opportunity. Like the very best of all the large performance saloon cars I have ever driven, the XJ seems to shrink around you when you need it to change direction quickly and often.This is largely because the suspension is soft and well-damped, which also has an enormously positive effect on the ride quality. If you have read other XJ reviews, this may come as a surprise, since the car has been criticised for having suspension that is too firm. In fact, this particular example reacted badly to sudden bumps in the road, but that had nothing to do with the suspension and everything to do with the 20" wheels and superlow-profile tyres (standard on Portfolio versions), and I'm surprised other writers haven't made the distinction.I haven't spoken to any Jaguar chassis engineers about the choice of tyres, but I imagine they're spitting tacks about it - combining that rubber with the XJ's kind of suspension set-up has never worked before, doesn't work now and is never going to work. The majority of customers seem to prefer the flashy look of those huge alloys over proper driving dynamics, though, and you can't blame Jaguar for offering them what they want. Engine 2993 cc, 6 cylinders Power 275 bhp @4000 rpm Torque 443 ib/ft @2000 rpm Transmission 6 speed auto Fuel/CO2 39.2 mpg / 189 g/km Acceleration 0-62mph: 6.4sec Top speed 155 mph Price From £68506.00 approx Release date 01/01/2010