First the good news. Mercedes have put their period of poor interior quality behind them. Sit behind the wheel of a B170 and apart from the nose which dives straight out of view, you could well be at the wheel of a big E-Class saloon or a beefy R-Class Sports Tourer. It features plastics quality that's so far removed from the normal family hatch fare that it barely stands comparison. The fit and finish is superb and almost smacks of the old school over-engineered Mercedes style. Step out and you'll think that Mercedes could ask a hefty sum for this car and you'd be tempted to stump for it.

The Germans don't disappoint. You'll need £20,130 for an B170 SE and virtually the same amount for the more aggressively-styled Sport variant. The closest rival to the B-Class is probably Ford's Focus C-MAX, another very well built five seater. Equivalent models retail at around £3,000 less than the Mercedes. So why bother? Try to justify it in purely financial terms and you'll soon come unstuck. The superior residuals of the Mercedes can't claw that premium back. If we're honest, it's all to do with badge equity. The plain truth is you'll feel better at the wheel of a Mercedes B-Class than you will if you've got a Blue Oval staring back at you and customers will pay for the premium.

Nobody likes to be suckered when buying a new car and the cynical may well point out that this so-called brand equity is simply a fancy way for the premium manufacturers to milk their label conscious customers. The reality is that it is, like anything else in the buying process, a transaction and like all transactions, it must fit the laws of supply and demand. Having sampled the B170, I agree that Mercedes will have no problem at all shifting their entire UK allocation. It's one of those cars you step out of and think, "I want one of them."

"The B170 may be stacked against some very talented opposition but none have quite the same reassuring implacability"

The first thing that will strike most observers is how much bigger the B-Class is than they expect. Pictures seem to show a chunkily compact little thing, but despite the fact that the B170 is a few millimetres shorter than a Ford Focus, it's tall and reasonably wide. It also tips the scales at 1,300kg and that's why the B170 makes such a decent choice. The model below this, the B150, has to make do with a weedy 95bhp engine that struggles to move it with any great alacrity. Load the car up with passengers and luggage and performance and economy take a real hit. Savvy customers will realise that the £1,200 or so to trade up to the B170 completely transforms the car's behaviour.

Instead of a 1.5-litre engine that gets to 60mph in 13 seconds, B170 customers get a far punchier 116bhp unit that'll knock a couple of seconds off the benchmark sprint without compromising fuel economy too seriously. Mercedes quote an average fuel consumption figure of 48.7mpg for the B170 which is quite some showing. If you're thinking of running one as a premium dual purpose company hack, you'll be pleased to hear that emissions are rated at just 163g/km.

In a bid to further drive down emissions and save fuel, buyers can now opt for a B170 BlueEFFICIENCY model which features an ECO start/stop function. This generates fuel savings of up to nine per cent in city traffic, the engine cutting out when the vehicle shifts to neutral at low speeds while depressing the brake pedal. A starter-generator fires the engine back into life far quicker than a conventional starter motor.

On the road? Well, don't get me wrong, the B-Class is no paragon of driving nirvana, but it's come a long way since the days of the infamous A-Class elk test. It handles tightly and competently, with perfectly placed pedals, very good body control, keen turn-in and brilliantly optimised electronic control systems. Keener drivers may complain about a slight lack of steering feel and fidgety low-speed ride but this is a far better handler than most would give it credit for. Even the basic architecture of the car does a lot to keep the centre of gravity low. There's far less body roll than you may expect for such a high-sided vehicle. With a little more weight to carry around than the equivalent A-Class, the B170 enjoys decent front end traction and the 116bhp output won't stress the traction control too heavily on dry tarmac.

Mercedes has worked to sharpen the appeal of the B-Class and the unassuming front end now looks a lot more purposeful thanks to revised headlights and grille. The rear styling has also been tidied up and there are now no models that don't sport body-coloured mirrors, door handles and skirt panels. The B-Class has always been more about the inside than the outside though. Sit in the back of a B170, stretch your legs out and you'll appreciate that it's comparable with the amount of room in the back of an S-Class limousine. Only those at the extreme end of the ergonomic scale will have any problems with head or legroom and there's ample room for three abreast. Despite this, the B-Class breaks the tape at only 4,270mm long. To put that figure into perspective, a Ford Focus measures 4,342mm from bumper to bumper, making this Mercedes something of a packaging marvel.

Mercedes dub the car a Compact Sports Tourer, but despite the great strides in driveability made by the A-Class upon which the B-Class is inspired, 'sporty' is perhaps a stretch too far. Still, although it won't make the cover of evo magazine, the B170 is nevertheless a decent steer. And a practical one. The rear seats all fold flat into the floor and the boot floor can even be raised to offer a flat loading surface. Other clever touches include a front passenger seat that folds forward to permit long loads and slots next to the rear doors to allow seat belts to be stowed safely out of the way when loading and unloading. The centre rear seat back can also pop forward, offering an armrest with a neat pair of cupholders when travelling four-up. The driving position is undeniably sporty. The wheel sits almost vertical and your legs stretch forward into a deep footwell. It almost feels like sitting in a jacked-up Lotus Elise but for the interior quality.

The dashboard is cleanly designed with a neat mix of contrasting colours and metallic detailing. Standard specification across the range includes air conditioning, a four-spoke steering wheel with multifunction buttons, an armrest between the front seats, electric windows and tinted glass, plus brushed aluminium trim on the fascia, transmission tunnel and door panels. Front parking sensors should have made the list too, as the front of the car slopes rapidly away and the body-coloured rubbing strips don't look as if they'd withstand too many scrapes with a concrete bollard before they started to look a little secondhand.

Mercedes have got all the basics right with this car but basics don't tease £20,000 cheques out of customer pockets. The genius in the B-Class lies in the way Mercedes have woven in a durable yet intangible thread of desirability. Making a bulbous 1.7-litre family hatch seem good value for money in this rarefied atmosphere requires some sly machinations and, once again, Mercedes are at the top of their game.

TOP 4 B CLASS DEALS

The results below show the top B CLASS deals on buyacar

	Mercedes-benz B Class B170 SE 5dr CVT Auto Hatchback
	ETR	Mthly £374	Saving £1,574	Price £19,971
	Mercedes-benz B Class B170 SE 5dr Hatchback
	ETR	Mthly £345	Saving £1,449	Price £18,676
	Mercedes-benz B Class B170 Sport 5dr Hatchback
	ETR	Mthly £343	Saving £1,449	Price £18,701
	Mercedes-benz B Class B170 Sport 5dr CVT Auto Hatchback
	ETR	Mthly £372	Saving £1,574	Price £19,971

typical 11.68% APR

PCP finance quote over 48 months,  10,000 miles pa,  deposit of £1000