AFTER just a few miles I realised I was in a rather tiny minority. In fact, the four-door, executive saloon complete with boot and traditional notchback design that I was driving was hugely outnumbered by hatchbacks, SUVs and even vans.

I drove for several miles along a busy A-road before another four-door saloon passed by - more than 30 vehicles later. Such is the change in buying patterns of the great British public.

The car that I was driving was in fact somewhat unusual - a BMW 5 Series with plug-in hybrid assistance. The 545e xDrive blends surprising frugality with serious neck-jerking acceleration and the sort or cornering that you'd hope for in a mid-engined sports car.

Some stats to engage with - under the bonnet there's a 3.0litre, six-pot coupled to a 107bhp electric motor knocking out, together, 389bhp. This, together with 443lb ft of torque means that you have enough clout to blow away all but a supercar, should you wish.

Floor the accelerator, and you'll eclipse 62mph in a mere 4.6 seconds.Top speed is electronically limited to 155mph, some 20mph below its natural max.

Cornering is near neutral with good steering feedback and very little body roll. Four wheel drive ensures all the power is fed down through the tyres without risk of scrabble.

Despite the endless supply of urge, most drivers will easily squeeze 38 to 40mpg from a gallon of E10. Our best result on a gentle rural run was 46mpg - almost incredible from a swift, luxury five-seater.

Particularly impressive is the fashion in which the miles are covered, Noise levels - both mechanical and wind intrusion - are barely audible. Only a degree of tyre noise over certain surfaces occasionally intrudes into the cabin.

The straight-six engine itself is a delight and emits a subdued growl - far from unpleasant - under hard acceleration. Throttle response is instant, made still quicker through the assistance of electric power.

The interior itself is, unsurprisingly, well finished and solid, if not terribly exciting, following the usual BMW template. A huge oblong touchscreen is set centre stage and the switchgear is a happy balance between new tech and easy-to-use touch-friendly knobs. It all works well and is pleasantly free from gimmicks.

Five can sit comfortably in the leather-seated cabin, but legroom in the rear falls short of several rivals and is tighter than in most medium sized SUVs. The boot, too, at 410litres is about one-third smaller than the non-hybrid version to make room for the electric gubbins, and considerably more compact than most SUVs.

Although there are ample storage bins and places to soak up the usual family clutter, pockets and cubbies are quite narrow and pokey compared with those generally found in crossovers.

The 545e pulls away from rest in electric mode and is capable of around 26 miles on pure electric power alone. With low CO2, it's a big attraction to company buyers keen on keeping BiK tax down to a minimum.