JUST like food portion sizes, coupes have got steadily larger.

The good news is that many are now full four-seaters which allow those in the back to stretch their legs a bit instead of wishing their growth had been curtailed aged 10. But the bad news is squeezing into supermarket car park slots is even tighter.

And with just two wide doors, getting out is trickier still.

The latest BMW 4-Series Coupe is only marginally smaller than the 6 Series from a few years ago.

Certainly, it's more elegant and graceful than its rather stumpy predecessor, the 3 Series Coupe, and the boot - 445 litres - is the size of a full-sized saloon, turning it into a genuine family proposition.

There's a huge choice of engines and the option of either diesel or petrol. Most popular in UK is the 420d and this car was equipped xDrive which is BMW-speak for four wheel drive, an increasingly popular choice.

Significantly, BMW xDrive models outsell Audi's home-grown all-paw quattro models.

Your performance expectations of a coupe are somewhat higher than for a regular saloon and the 182bhp 420d delivers the goods without making much of dent in your wallet when it comes to fuel station visits.

With a CO2 emissions level of 125g/km the official combined average is 60.1mpg which means in real life driving most owners will hit the 45mpg mark.

The four-wheel-drive systems adds a bit of weight which inevitably has marginal adverse effect on fuel consumption, but the BMW system is lighter than many.

Acceleration to 62mph in 7.5 seconds puts it in the right bracket for a businessman or woman in a hurry with long distances to cover.

The four cylinder engine is a shade grumbly at tickover, but smoothes out in mid-range before becoming more vocal again towards the limit. There's not much point in hanging onto the revs because there's ample torque - 280lb/ft - to allow swift high gear overtaking.

An eight-speed ZF automatic gearbox is slick and matches the car's character perfectly.

With a low centre of gravity and intelligent four wheel drive, the 420d with adaptive M Sport suspension feels pleasantly well planted on the road.

In all but extreme conditions cornering is neutral with little body roll. The steering is well-weighted but doesn't pass much road information back to the helm, however.

Big alloys shod with low profile rubber tend to make the ride a bit knobbly at low speed but it settles down as speed mounts.

The cabin is pure BMW with lots of high grade dark plastic, solid switches and sensibly placed dials.

It's not the most exciting driving environment but it's practical and it feels as if it would stand the test of time. It's family-friendly enough with ample cup-holders and cubbies for picnics and everyday use.