You don't need to be that old to recall a time when only genuine supercars could post a sprint to 60mph in 6.5 seconds. These days, that sort of figure can be scalped by hot hatches, budget roadsters and now there's even a diesel-engined executive smoothie that boasts this sort of sprinting ability. BMW's 535d wrested the title of fastest accelerating diesel production car away from rivals Audi and offers the sort of all-round performance that forces one to ponder the relevance of petrol power in this class of car.

Ignore that 535 designation; there's no 3.5-litre lump under the bonnet of this Five. Instead there's a three-litre engine that features two turbochargers of significantly different size. The smaller of the two blowers doesn't take a lot of energy to spool up and comes on stream from idle through to 1,500rpm, whereupon the engine's exhaust gases can overcome the inertia of the bigger of the two units. From around 1,000rpm these two units operate together but from 2,500rpm up to the 5,000rpm redline, the big turbo is operating on its own. Peak power arrives at 4,400rpm where this engine is making a crushing 286bhp. Even more impressive is the 580Nm torque figure - more than a Porsche 911 Turbo. If you're really into your engines, you might well have twigged that this powerplant is cranking out a higher specific output than any other diesel. Even if you're not technically minded, let's just say that this is a very advanced piece of plumbing.

So muscular is the £39,410 535d that BMW's standard manual gearbox would be turned to swarf by the torque of this engine. Instead the 535d is fitted with a slick six-speed ZF automatic gearbox and will command a premium of just over £3,000 versus the equivalent 530d automatic. What is particularly impressive about the 535d is the way BMW have overcome the downsides of driving a turbodiesel car. The rather unsatisfying 'bog and surge' power delivery of many turbodiesels has been completely nullified by the clever sequencing of the turbochargers, ensuring a clean, even spread of power from idle right up to redline. An electronically limited top speed of 155mph is as quick as you'll likely ever need and makes the powerful petrol engined 5-series models seem strangely superfluous. You don't buy a car like this on the strength of fuel economy but the 535d nevertheless returns predictably excellent figures. A combined showing of 40.9 mpg will make planting the throttle a refreshingly guilt-free experience. Likewise, if you're a company car buyer who has some rather serious clout, the 178g/km carbon dioxide emissions figure is a bit of icing on the cake.

"So muscular is the 535d that BMW's standard manual gearbox would be turned to swarf by the torque of this engine"

What this car is all about is effortless muscle. There are quieter diesel engines, Jaguar's latest V6 for one, but none offer this combination of power and flexibility. The advanced software of the automatic gearshift coupled with a torque band with fewer holes in it than the Chelsea defence means that there's instant urge available from virtually any point on the scale. The 535d even shapes up comparatively well in terms of price. Suddenly £36,000 for 224bhp worth of Mercedes E320CDi seems like a lot of money.

And that styling? Well, the once radical shape of the 5 Series has now matured nicely into a discreet but smart piece of design. In a bid to keep things fresh, BMW has made a few small changes to the latest car. At the front, the headlights and indicators are now clear glass while the kidney grille sits flush with the bumper. The air duct in the rear valance has been revised while the side sill gets an additional contour line and horizontal LEDs are used in the rear light cluster. Inside, the door panels and window switches have been redesigned and there's now eight freely programmable 'favourites' buttons on the dashboard so that drivers don't have to use the infernal iDrive control system quite so much. There's also an optional Lane Departure warning system offered.

The 5 Series remains a big but not bulky car. The saloon gets decent space up front with slightly below average rear leg room and a 520-litre boot. Measuring 4.48m in length, the Touring estate features a 535-litre load capacity with the 60/40 split folding rear seats in place and a hefty 1,650 litres with the seats folded down. There's also a split bootlid with the rear window opening separately for the easy loading of small items. Customers can also opt for a fully-automatic tailgate operation with a press on the key fob opening the hatch and simultaneously retracting the boot load cover.

Dynamic Drive, BMW's active suspension system, is available as an option, and Active Cruise Control, a system that automatically controls distances to the car in front, is also available to order. BMW hasn't left too many safety features out of the 5-series. Brake Force Display is an interesting concept, enlarging the brake light area when the driver really anchors on. Another first for BMW is Adaptive Headlights - a feature many will associate more with Citroen. This system, sadly still an option, swivels the headlights by up to 15 degrees left and right to illuminate more of the road through a bend. Unlike Citroen's rudimentary old mechanical system, this calculates speed, yaw rate and steering angle before steering the beams. Another technology 'borrowed' from another manufacturer - in this case Chevrolet - is an optional Head-Up Display that projects information onto the windscreen.

Leaving aside the 535d's slightly controversial styling, it has to be said that on paper, this is the best executive car there is. If you can live with the lines and have the funds to absorb the up front costs, you'd be mad not to try it

TOP 4 5 SERIES DEALS

The results below show the top 5 SERIES deals on buyacar

	BMW 5 Series 535d M Sport 4dr Step Auto Saloon
	ETR	Mthly	Saving £2,970	Price £39,950
	BMW 5 Series 535d M Sport 5dr Step Auto Touring Estate
	ETR	Mthly	Saving £3,156	Price £41,814
	BMW 5 Series 535d SE 4dr Step Auto Saloon
	ETR	Mthly	Saving £2,686	Price £37,114
	BMW 5 Series 535d SE 5dr Step Auto Touring Estate
	ETR	Mthly	Saving £2,873	Price £38,977