BMW's sixth-generation 3 Series has evolved to meet the needs of the 21st century, says Iain Dooley, PA senior motoring writer.

IF BMW is feeling the pressure regarding the launch of its latest 3 Series saloon, it's doing a good job of hiding it. When you make a car that forms a fifth of your total sales it's important to get it right. But the German firm's had plenty of practice, as past generations of the car have been well received.

The previous model wasn't perfect, though. Rear-seat occupants could have done with more legroom and the performance-oriented M Sport models were probably a little too extreme for some as the ride was on the harsh side of firm.

In its new 'F30' guise, this latest 3 Series saloon addresses such shortcomings and goes further regarding engine performance and economy. Many cars will end up in the hands of company-car drivers, making fuel economy and emissions gains key to its future sales success.

This 3 Series adopts many of the styling cues of the 5 Series. The F30 3 Series is not only different on the outside, it's also bigger on the inside. Longer in length and wheelbase, it's the latter that allows rear-seat occupants to stretch out.

The cabin is plenty big enough fore and aft, with the driver-centric fascia easy to use as everything is close to hand. BMW has squeezed more space out of the boot, plus there's a through-load option further enhancing its practicality.

BMW is taking a bold decision to separate the sporting and luxury equipment lines. The value-based ES and SE models remain, and Sport and M Sport have been joined by Modern and Luxury variants offering more luxurious trim to try to lure Volvo, Lexus and Jaguar drivers out of their plush cabins.

For many 3 Series fans it's the way the car drives that will be the main appeal. BMW's ability to keep a lid on any weight gains has helped agility and economy. Furthermore, advances in the engine department have seen power and efficiency gains across the board, while alongside the standard six-speed manual gearbox there's a new eight-speed automatic.

The all-turbo line-up runs from 316i to 335i, but all-important diesels will take a considerable proportion of sales. In 320d guise, power output is a healthy 184hp while economy is a claimed 61.4mpg. Factor in tax-friendly 120g/km CO2 and it's not hard to see this variant as a staple on company car user-chooser lists.

SE wants for little in terms of equipment and on-road ability but move up a notch to Sport trim and added cosmetic and comfort items of kit should make the ownership experience that bit more enjoyable.

Sport trim gives you the chance to experience BMW's range of M Sport performance options such as adaptive suspension. Previous M Sport cars were really for hardcore fans, but now the proposition is more forgiving. The ride is very supple over poor roads yet body roll is minimal so you can attack corners with confidence and vigour.

Combine this experience with the 320d's elastic power delivery and you've got a potent machine. It'll sit at motorway speeds all day without complaint, but when you want to have some fun it'll deliver a near-flawless performance with none of the compromises of the old car.

And if you're not into wringing every last drop of performance from your new 3 Series, there's the 320d Efficient Dynamics to consider. This is BMW's eco-champion boasting 109g/km CO2 and 68.9mpg in manual guise. There's 163 rather than 184hp but refinement and equipment have not been sacrificed for tax-beating economy. And it too can be had with the eight-speed automatic gearbox.

All cars get standard iDrive controller and colour screen and Bluetooth hands-free.

Now in its sixth generation, BMW's 3 Series saloon has evolved into a car with a wider remit to please, thus ensuring a broader customer base and healthy future sales. It's still the Ultimate Driving Machine but evolution dictates it just means something else in the 21st century.