FEW cars have thrown up so many conundrums for me as the new Mercedes-Benz B-Class.

On the one hand it is much roomier than its predecessor with a tangible improvement in trim quality and a genuinely luxurious feel.

Dynamically styled, sleek and sporty and packed with advanced safety technology, it is also fitted with one of the most intelligent satellite navigation systems I have ever used.

Then there is the engine. On the test model, it was a new 1.8-litre turbo diesel engine delivering the tempting prospect of well over 60mpg in day-to-day travel.

All well and good then, but it was the engine that threw up the first puzzle. Fire it up from cold and there is a real old-fashioned diesel clatter that persists until the car hits 35mph, when it smooths out and the car’s poise returns.

The second irritation came from the decision to install an electronic parking brake as standard. Many manufacturers have gone down this route as it is a neat solution that frees up the space between the front seats. But while many disengage automatically as soon as the accelerator is pressed, the B-Class brake needs to be set and released manually which, in heavy traffic , and combined with a manual gearbox, quickly becomes a real pain.

Like anything, you learn to live with these irritations but they are not what you expect in a classy range of cars that start at just over £21,000.

On the plus side, the B-Class, especially when fitted with the lower sports suspension, firmer springs and dampers, and faster-acting steering, is superbly nimble.

Light and manoeuvrable around town, the five-seater is sharp and precise on country roads and settles down at speed to deliver relaxed cruising. Wind and engine noise are muted at speed but the wide tyres fitted to the car’s 18-inch alloy wheels suck up road noise.

Safety technology is superb with a radar-based system that warns if the set safety distance from a vehicle ahead narrows.

All models are also fitted with an attention-assist system that continuously monitors steering and alerts a potentially tired driver with a ‘take-a-break’ warning. The big-screen colour satellite navigation system can be operated by voice and simply reading out a street name and town proved enough to accurately set a destination, with none of the prolonged button pushing or dial clicking that some systems demand.

The B-Class is the first Mercedes-Benz to have been designed without a spare wheel well, which saves space and weight. The Sport model comes with special tyres, which feature full run-flat capability but with softer sidewalls so they do not impact on ride comfort.

The quality of the interior is a marked improvement conjured up by a sumptuous blend of man-made leather, silver chrome and satin-finish polished aluminium. It is just as practical as it is glitzy with plenty of cabin space for five and a whopping boot.

There is plenty of choice in the new B-Class range with 14 models, four engines, two transmissions and two trim levels.

Auto facts

Model : Mercedes-Benz B 200 CDI BlueEfficiency Sport

Price : £24,710

Insurance group : 20 (1-50)

Fuel consumption (Combined): 64.2mpg

Top speed : 130mph

Length : 435.9cm/171.6in

Width : 178.6cm/70.3in

Luggage capacity : 17.1 cu ft

Fuel tank capacity : 11 gallons/50 litres

CO2 emissions : 121g/km

Warranty : Three years/unlimited mileage