When the Volkswagen Group announced its Modularer Querbaukasten platform (mercifully abbreviated to MQB) a few years ago, it promised us that it was flexible enough to be used for cars of all different sizes. This has already been shown to be true, and it looks like it's going to become even truer: there is now talk that everything from the up! city car to the Touareg SUV may share essentially the same underpinnings.
Roughly halfway between those extremes lies the 2015 Passat, the eighth model of that name in a line stretching all the way back to 1973 and the first to benefit from MQB technology. It's almost exactly the same length as Passat 7.0 (actually two millimetres shorter, but a few bugs slamming into the front bumper will soon make up the difference), a little wider and quite a bit lower. The front and rear axles are much further apart, which as we'll soon see has a big effect on interior space, and various cunning ploys mean that each model is up to 85kg lighter than the one it replaces.
There are saloon and estate body styles but no hatchback, which is probably going to hurt UK sales because we do like our hatches, and a range of diesels with power outputs from 118bhp to slightly more than twice that but not a petrol engine to be seen. Not in this market, anyway.
Why not? Well, 80% of the seventh-generation cars were sold to fleets, and fleet buyers love diesels because of their fuel economy, their low official CO2 emissions and their cheapness to tax. Of the private buyers who bought the previous model, only one twentieth opted for petrol, so the decision was made at Volkswagen UK's Milton Keynes headquarters to focus exclusively on diesel this time round. You can still buy a petrol Passat if you really want one, but you'll have to go abroad to do so.
At one end of the scale you can have combined fuel economy in the high 60s mpg, at the other (with the twin turbo BiTDI 2.0-litre engine) a maximum output of 237bhp and a 0-62mph time of under seven seconds. Whether you pick either of those, or the 187bhp 2.0-litre, or the 148bhp version which VW reckons will be the unit of choice in this country, you're going to have to deal with a level of engine noise which wouldn't have been considered objectionable ten years ago, but is disappointing in a Volkswagen of the current era.
There are other causes for gloom. On the roads of Warwickshire, not one of four Passats I drove on the media launch rode well, feeling as if nobody had told the German suspension engineers what British tarmac is like even though they must surely have some idea by now. Curiously, the worst offender was the cheapest 1.6-litre S model, which was a surprise because basic Volkswagens are often the nicest to drive. More expensive versions with larger wheels and lower-profile tyres are, most unusually, more comfortable, but none of them are as good as they should be.
Changing gear smoothly in manual-transmission models is unexpectedly troublesome. And, as in the Golf, an otherwise high-quality interior is spoiled to some extent by rotary air-conditioning controls that seem more suited to a budget car than a premium one.
But there are compensations, the outstanding one being the amount of room for front and rear passengers. I'm more than six feet tall (by accident rather than as part of any carefully worked-out plan) and you could fit four Davids in the Passat without the least trouble. Luggage space is impressive too, at 586 litres for the saloon and between 650 and 1,780 litres for the estate, depending on what you do with the rear seats.
All those figures exceed those of the previous Passat. More importantly, they also put the Ford Mondeo and Vauxhall Insignia, the leaders of this class in the UK, well into the shade.
The hatchback issue, however, is problematic. The saloon may have a large boot, but its small opening, dictated by how far back the fixed and slightly coupe-style rear window goes, means that objects which could sit inside can't actually be put there. If you want more practicality you must spend an extra £1,530 on the estate, and not everyone wants their car to be that kind of shape.
The handling ability of most versions is reliable and undramatic, which is fine. Not many people drive Passats for the thrill. The BiTDI is an exception: dividing its considerable power among all four wheels means you can apply it quite forcefully in mid-corner and on to the next straight, if you're in that sort of mood.
The entry-level S is reasonably well-equipped, and the others boast a lot of technical features. Among the optional extras are the Car-Net online system which operates through an Android smartphone, Predictive Pedestrian Protection, Traffic Jam Assist (which basically lets the car do its own thing when there's a lot of stopping and going to be done), Emergency Assist and Trailer Assist.
That last one is most impressive, since it allows you to reverse a trailer into even quite tight spaces without turning the steering wheel. In fact, if you do, the system assumes you're taking over and switches off automatically.
Trailer Assist takes some learning (counterintuitively, you tell the trailer where to go using the knob that otherwise controls the position of the door mirrors) and you have to know a bit about towing to be able to use it. But it enabled me to reverse a trailer round a 90-degree corner to where I wanted it to be in one go, rather than in five or six as would almost certainly have been the case if I'd tried to do it on my own.