BMW is hoping to make up for lost time, by finally introducing a diesel version of its 7 Series executive saloon model.

Competitor Mercedes-Benz says that oil-burning versions of its rival S Class now account for the majority of sales, as is the case with an increasing number of luxury saloons.

Now BMW is adding a diesel option, with Audi planning a hugely powerful one for its A8, and Jaguar desperately attempting to get a diesel version of its new XJ saloon to market too.

BMW's offering is a three-litre six-cylinder unit that utilises the second generation of common rail (economic and clean) diesel technology.

Reassuringly smooth and quiet, it develops a hefty 218bhp, with 369lb.ft of torque from 2000rpm.

This endows the car with a brisk 0-60mph acceleration time of eight seconds, and a top speed slightly in excess of 145mph.

For United Kingdom drivers, this means genuinely effortless cruising at the motorway maximum, with guaranteed economy of 33mpg.

This diesel version benefits from a new six-speed transmission with Steptronic, which becomes available across the entire 7 Series range.

Although there is a slight audible difference between this new engine and the petrol-powered versions from outside at tick-over, it is virtually impossible to tell them apart once on the move.

The 730d feels impressively smooth and quiet throughout the rev range, and at cruising speeds the engine is virtually silent. Apart from the obvious financial benefits of running a diesel-powered car, plus the convenience of longer ranges between fuel fill-ups, there is the massive mid-range pulling power.

Allied to the new six ratios to make the most of this, it enables the 730d to haul hefty loads effortlessly, with five adults and a full load of luggage making little impression upon the performance.

The CO2 figure of 227 grammes per kilometre makes the 730d the most tax efficient model in the 7 Series range, with prices of £44,555 for the standard 730d, £46,555 for the 730d SE, and £48,755 for the 730d Sport version. BMW is aiming to sell more than 1,000 of the diesel models this year, which will be almost 40 per cent of all 7 Series sales in this country.

BMW has made it easier to get behind the wheel of its most expensive models, by making them cheaper.

The flagship 7 Series saloons now come with a choice of three-litre petrol engines, together with the three-litre diesel, with prices from £46,850 for the 730i, £48,850 for the 730i SE, and £49,450 for the long wheelbase 730Li model.

The 231bhp three-litre straight six petrol engine endows them with rapid acceleration to 60mph in just over eight seconds, with a top speed in excess of 145mph, and economy of about 26mpg.

As with all 7 Series models, they come with the benefit of a six-speed transmission with Steptronic to make the most of the power available.

The long wheelbase version, which also comes with the ultimate option of a hugely powerful six-litre V12 engine, is five and a half inches longer than the standard model.

Even in 730Li guise it has leather upholstery, electric sun blinds for the rear and side windows, plus self-levelling air suspension. Like the 730i and 730 Li, there are 760i and 760Li variants, with the V12 engine generating a whopping 445bhp of power, and an awesome 442 lbs ft of torque, or pulling power.

This translates into a 0-60mph acceleration time of just five and a half seconds, with an electronically limited 155mph top speed.

The 760i, which manages an average economy figure of about 20mpg, costs £76,350 in standard form, and £78,450 in long wheelbase guise.

In addition to the 7 Series additions and enhancements, there are changes to the 3 Series coupe and convertible ranges too. Together with minor cosmetic improvements, there is a new six-speed sequential manual gearbox as an option on the BMW 330i and BMW 325i coupe and convertible, as well as the chance to mix it with F1 paddle shift gears on the steering wheel.

Dynamic stability control becomes standard across the 3 Series range, and there is a new six-speed manual transmission on all 330Ci coup and convertible models. The new six-speeder is also on the 330i and 330d saloon and touring models, the 320d saloon and touring, and the 320td and 325ti compacts.

Thankfully, it seems, very little has changed in BMW's philosophy towards its coup models. The latest, now in its sixth incarnation as either a two-door sports saloon or coup, features a number of stylish design enhancements rather than dramatic changes.

For example, there is a re-styled front bumper, re-styled side indicators in the front wings and new back light clusters, while the bonnet has been given a slightly raised dome look.

Updated: 12:11 Friday, June 06, 2003