It’s put-up-or-shut-up time for Infiniti in Europe. And after what even they’d describe as the slowest of slow starts over the last three years, Nissan’s premium arm finally seems to be having a decent crack at putting up.

The Japanese luxury car brand is using this Geneva motor show to introduce its new rival for the BMW 3-series: the Q50. Unlike the G37 before it, this car is right-sized for its class. And having seen it close up at a preview event last night, I can confirm that it’s an appealing car.

A bit fussy-looking here and there, but still much more striking than any of the brand’s current saloons, and better proportioned.

More important still, it’s going to launch this summer with the same 168bhp 2.2-litre four-cylinder diesel engine you’ll find in a Mercedes A- and B-class, emitting a competitive 115g/km. It’s the lack of a decent four-pot diesel, more than anything, that’s held the Infiniti brand back in Europe. The Merc one isn’t the best on the market, but it’s competent. And after what they did with Renault’s 3.0-litre V6 diesel for the FX, EX and M models, the firm has already proved that it can put manners on any powerplant.

There will also be a 359bhp, 145g/km petrol-electric hybrid offered.

The press material makes a great deal of the Q50’s long wheelbase and roominess. It’s got good legroom; plenty of headroom in the front, not quite as much in the second row. Overall, I’d say a BMW 3-series is a more spacious car – but only just. And from where Infiniti was on packaging - with the likes of the EX and M way behind the class standard on practicality - it’s a bit of a result. Material richness and cabin quality both seem particularly lavish.

The Q50’s all-electric steer-by-wire system is its technological highlight. It adds little by way of fuel-efficiency compared with a simpler electromechanical power steering system; the benefits are all about configurability and ease of use.

There’s no bump-steer, they say: you can drive the car at speed over ruts and big cobblestones and feel no disturbance at all through the rim. You steer straight, the car goes straight: that’s it. Directional response is improved. You can also adjust the pace and weight of the rack to your heart’s content. But will it feel trustworthy; 'real'? We’ll find out when we drive the car in June.

Meantime, there’s another new Infiniti to consider further off. The firm’s premium compact hatchback – answer to the Audi A3 and BMW 1-series – has already been confirmed for production at Nissan Sunderland. The design is complete, and dynamic development is well advanced.

“It’s a much more emotional design than the segment has currently,” said Infiniti design supremo Shiro Nakamura. “It could have as much visual impact as the Juke. It’s based on Daimler’s platform (A-, B-class). It will be five-door only, and it has the same wheelbase as the A-class, I think. But it’s lower, leaner than the Mercedes: something very special. Not so much like the (Etherea) concept, actually. I’m truly excited about it.”

Apparently it could be called ‘Q30’; it could be called ‘QS30’. Whatever it’s called, it sounds like very good news, both for Infiniti and for the British car industry.