FOR those who haven't yet come across the Infiniti brand, let me explain. It's a sort of posh arm of Nissan in the same way as Lexus is to Toyota.

The global marque was launched in UK around the start of the credit-crunch, which is probably why it has taken a while getting a foothold in the contracting prestige marketplace.

The Q50 I've been driving is actually a replacement of the Infiniti G37 which had the tough task of challenging the likes of Merc C-Class and 3-Series BMW.

Slightly longer and lower than the old version, the Q50 cuts a bit of a dash with its swoopy, flowing lines and its squat stance that shout sport saloon loud and clear.

Two models come to Britain - a 2.1-litre diesel and a much more powerful 3.5-litre V6 hybrid which knocks out a heavyweight 359bhp when coupled to an electric motor.

Performance is above the class average with a restricted 155mph top speed and a dash to 62mph in a swift 5.1 seconds, but economy, thanks to the hybrid design, is more like that of a 2.0-litre diesel with an official combined figure of 45.6mpg and emissions of 144g/km.

Like most hybrids, normal driving with surges of acceleration for overtaking and stop-start running, takes its toll and my average was just over 35mpg - still impressive for this level of performance.

Not only is the Q50 - price £41,810 - more svelte and glamorous on the outside than the G27, its cabin is better planned and beautifully appointed.

The dials are sensibly grouped and the switchgear and controls is of the highest standard. There's a real sense of occasion for driver and passenger and the conventional rear boot is 20 litres larger with at 500 litre capacity.

A standard seven-speed automatic transmission feeds power to the rear wheels. It's generally a smooth system but on occasions there's a ‘stutter' during the transition from electric power at low speed to the petrol engine. Kickdown is quick and responsive.

Grand Prix champ Seb Vettel is said to have had a hand in advising on handling set-ups with sporting Infinitis, yet the Q50 fails to match the dynamic prowess of Jaguar, BMW or Mercedes in this area.

Handling is safe and predictable, but the level of adhesion over greasy or muddy roads is too limited, provoking the interception of electronic aids. Noise suppression is good with little mechanical intrusion or road noise, making the Q50 an easy and relaxing express in which to swallow up motorway miles.

There's plenty of tech packed into the new car including Direct Adaptive Steering with options for variations of ratio and resistance through a drive-by-wire system.

Active Lane Control and Distance Control Assist which are designed to keep you safer are also present, if these types of developments are your bag. Some drivers may find them over-intrusive...a shade of Big Brother.

With an impressive turn of speed and good economy alongside genuine road presence the Q50 deserves to be well received as an interesting new arrival in the executive car park.