These are the Jaguar XE's rivals

So, a supercharged Jaguar XE is A Very Good Thing. And that's important - for the XE to prove itself as a sports saloon gives the range kudos alongside the likes of the BMW 335i and forthcoming Mercedes-Benz C450.

So that's all well and good. But, be honest: you're not thinking of buying a supercharged XE, are you? No, you've heard about the new-generation Ingenium engines and have probably had a sneaky look at your company-car policy, or the lease deals available, and you're thinking the diesel XE looks like it might be A Very Good Thing too. Prices from £29,775, 161 or 178bhp, satnav standard on every model in the range, CO2 emissions below 100g/km, free road tax. All that stuff that would allow you to justify a Jag. And justifying a Jag, making it stack up financially as well as emotionally, isn't something that's been possible for a long time, perhaps ever (no, the X-Type doesn't count).

Pictures: Lee Brimble

This feature originally appeared in the February 2015 issue of Top Gear Magazine

But there's a thing, and the thing is that the Germans are persistently, annoyingly brilliant. We've ignored the Audi A4 because it's a spent force these days, soon to be replaced, but the BMW and the Merc? Much tougher to argue against.

The C-Class channels the luxury spirit of the S-Class into a smaller package. Distilled essence of S. There are strong arguments to say this is a more desirable, more creative and better targeted car than the bigger E-Class. It's tremendous. Meanwhile the BMW 3-Series has never been stronger: it's a brilliant all-rounder, the class benchmark, wonderfully easy to get on with and affordable to run, but able to dissecta corner with real panache if the occasion demands.

Now, just so we're clear, we did not have all three cars together in the same place at the same time. I spent a week tooling around the UK in the BMW and Mercedes before heading out to Portugal to drive the Jaguar. Nor do we have perfectly matched examples. The BMW is a 4wd 320d xDrive; the Merc, a 201bhp C250, rather than the more power-appropriate and sales-popular 168bhp C220. And in this class, the devil is in the detail. The odd gram of CO2 here, a stray option there and the deal could be broken. Money matters; running costs matter. Do without 4wd, and the BMW is the cheapest by over £1,400. Drop to a manual C220, and nothing can match its promise of 70.6mpg.

We haven't got the space to deal with the finer points of the spec sheets here, but all three are equipped with auto 'boxes and in sportiest trim. For Jag, this means the 178bhp version of the new 2.0 Ingenium diesel, complete with 8spd auto and R Sport trim. It's the exact model Jag has the most pre-orders for.

As Jason pointed out, there are things we have to ignore on these final-stage prototypes. The diesel suffers from excessive turbo whistle, to go with the untextured cabin plastics. There was no mention of any gearbox issues, but I'd be surprised if the calibration wasn't due a couple more tweaks - BMW uses the same ZF gearbox and in the 320d it's peerless, while here it was a bit jittery through the lower gears. No complaints if you choose to self-shift, though.

Expecting the XE to be revolutionary, to set new standards across the board? The competition is too talented for that to be the case. Jaguar makes much play of the XE's aluminium-heavy body structure, but at 1,565kg, it's merely class-competitive. Same goes for the Ingenium engine. It has a lovely slug of mid-range power, but that tails off quite soon, and yes, you can tell it's a diesel. Smooth and admirably free of clatter it may be, but the noise is there.

But what matters is how it feels on the road, and Jaguar's pitch is simple: "The driver's car in the global premium midsize saloon segment." The italics are Jag's. It has to beat the 3. So you expect it to be sporty, but actually the XE is closer in execution to the C-Class, majoring more on comfort and relaxation.

You may find this disappointing, but it's an intelligent strategy. The BMW is a fraction nervous, demands concentration, the Mercedes is a bit hefty on the road, but the XE comes across as a beautifully oiled product, fluid and capable. The ride is peerless; motorway behaviour, fabulous. Yes, it's a shame steering feel is lacking, the front end isn't a bit sharper and it doesn't properly suck you into a good road like the eager BMW, but as an everyday car, it's massively impressive, so composed and hushed.

The class-leader? We can't give a definitive verdict until we have them all on the same road, but each of these three has an area it excels in, a compelling reason to choose it over the others. The Merc has the best cabin and feels the most upmarket. Nothing has changed to knock the BMW off its driver's car pedestal. The Jaguar is effortless. You'll choose the car that suits you best, but what's important here is that Jaguar has built a compact saloon that can stand up and be counted alongside the best in the world. For the time being, that's enough.