There are a few phrases a motoring journalist does not want to hear when testing a new car. These include: ‘we need it back in 10 minutes’, ‘we’ve jammed the traction control on,’ and ‘we’ve told the police you’re coming.’ And if you think the last of these is what passes for humour in this neck of the woods, I can assure you it is not. Manufacturers also love to ask what you think of the car, in the hope that the fact they’ve put you up in a five star hotel will make you feel awkward about saying it’s rubbish. And then if you’re nice about it to their face, you’re going to find being rude about it in print incredibly difficult. Which, of course, is why they ask.

But there’s another phrase that’s almost equally awkward to deal with, and it’s the one that goes: ‘just need to let you know this is a pre-production unit.’

Seems innocuous enough doesn’t it? But it’s not – it provides the manufacturer with an excuse for every single thing you might not like about the car. If the car has terrible wind noise or an unsettled ride, dodgy panel fit or any other sub-optimal feature, it can all be put down to the car being a pre-production prototype. Then again as journalists we can’t really turn round and say, ‘I’m sorry but if you can’t provide a representative model I’ll wait until you can’ because by that time so many thousands of stories about the car will have been published no-one will read yours, which rather defeats the point.

But there can be no doubt that the new Jaguar XE I drove at Estoril and on the roads nearby really was a pre-prod unit. I’ve seen TVRs with more consistent panel gaps and DIY kit cars with fittings of higher quality than some of those inside the XE. And given that it is an entirely new car built in a brand new state-of-the-art facility I think allowances for such issues can safely be made.

Besides, I’ve driven many very definitely production specification cars that felt less together than this. Most of them in fact. Over the next few weeks you’re going to be reading a lot of sentences containing the words ‘the XE is the most important Jaguar saloon since…’ and then likely or not their author will pick the original XJ6 or the MkII to make the point. Actually I think the XE is more important still, because those models stood alone, while the XE will beget an entire new generation of Jaguars, including not only the obvious estate but also the F-Pace SUV, and in time a coupe and convertible too.

So far as I can tell from the pre-production models I drove, the car is nearer outstanding than merely good and when you consider that Jaguar made just over 80,000 cars last year while BMW made 1.8 million (not including Mini), the scale of the achievement is astounding.

What I want most from a Jaguar is a car that looks good and then proves better even than that to drive. And that is precisely what even the inexactly constructed XEs I drove provided. I drove one on sport suspension boasting the new ‘Ingenium’ 2-litre four cylinder motor and another with adaptive damping and a supercharged 3-litre V6 under the bonnet. Dynamically at least, both seemed likely to lead their class. I drove them on some of the worst roads in Europe and found cars with a chassis able to offer poise, precision and comfort like no other I know in this category, not even the BMW 3-series.

There were aspects I didn’t care for so much – the electric steering was good but not as good as Jaguar’s best hydraulic arrangements – while the Ingenium was noisier than I’d have liked. Jaguar claims both will be improved before customers take delivery, but we shall have to wait and see. I think the Mercedes C-class has a prettier and far more luxurious interior and an Audi A4 a clearer and more attractive way of presenting its information.

But overall? If, as Jaguar insists, the production XE really does smooth off the rough edges of the prototype I drove, it will be at least comparable to the best in the class and to an extent where the one you chose would depend far more on personal preference than one car’s clear superiority over the other. For Jaguar and for its bosses at Tata in India who had the faith to back its engineers and let them create the car they wanted, that will be a fabulous achievement. What’s more it will silence forever those who point at its predecessor, the frankly fairly awful X-type, and say Jaguar should not be in the business of building small, high volume saloons. On the contrary, with a car as apparently good as this, that is not only a business it should be in, but one in which it should compete with startling vigour for many years to come.