Compare the fastest diesel cars

Best for: diesel performance

Mercedes has been a firm believer in big, quick diesel engines for years, and its latest E 450 d has the title of the fastest diesel on sale in the UK. It’s a heritage that goes as far back as the 1990s with the E 320 CDI - the top-of-the-line diesel at the time which could crack 0-62mph in 8.3 seconds; almost as quickly as the petrol-powered E 320 could.

Technology has certainly moved on since then, and today’s top-spec diesel E-Class will leave its great-great-great-grandfather in its dust. A 367hp inline-six 3.0-litre engine with 750Nm of torque will propel the four-wheel drive E 450 d to 62mph in just 4.8 seconds and on to a top speed of 155mph. The E 450 d’s mild-hybrid system adds an extra 23hp too. Those are serious figures, faster than any of its petrol-powered E-Class alternatives without dipping your toe into the AMG model range.

The E 450 d can achieve up to 47.1 mpg too, and long-distance drivers with a light foot should be able to eke out 683 miles from a tank of fuel. The performance comes with a price though, with the 450 d model starting from just shy of £90,000.

That’s not to say the E-Class is bad value though. It’s a very comfy drive, with plenty of adjustability, space inside and a fantastic ride - especially on its optional adaptive suspension which is a must-have. Long-distance drives are a piece of cake with little in the way of engine and wind noise.

Best for: fast, diesel-powered luxury

Sharing the same engine as its smaller E-Class sibling, it’s little wonder that the top-spec diesel S-Class barely trails it when it comes to performance. The S-Class is the flagship Mercedes saloon after all, so you can forgive it for being ever-so-slightly slower in the name of equipment, technology and sheer size.

As with the E-Class, the S 450 d is powered by a 367hp inline-six 3.0-litre engine with an additional 23hp electrical boost thanks to its mild-hybrid system. A total of 390hp and 750Nm of torque are enough for a 5.0-second 0-62mph time; plenty fast for a two-tonne luxury saloon.

Again, because of its bigger footprint and weight, the S 450 d concedes about 50 miles of range to the E 450 d at 646 miles to a tank, but that’s not an enormous difference.

And the S-Class’s reputation as being one of the most pioneering cars in the world is fully intact - even with a sporty diesel engine under the bonnet. The interior of the S 450 d is a very special place to be, posher than any other Mercedes on sale. Lashings of wood and metal detailing surround the cabin, as does hide upon hide of leather.

Ambient lighting sets the mood, but the floating central screen controls the S 450 d’s settings. There are still some physical buttons, but the screen controls the air-con and menu features of the S-Class. Not always a plus, but the driving experience is made simpler thanks to the level-3 autonomous driving mode.

The S 450 d isn’t a radical departure from Mercedes styling, unlike its electric EQS alternative. It’s a traditional saloon, with an upright grille and a curved roofline leading into a distinctive boot. You can tell that Mercedes is proud of the S-Class heritage, so it’s not gone out of its way to fix something that isn’t broken.

The LED headlights and taillights are slimmer than the previous model though, definitely sportier and sleeker, but the upright three-pointed star ornament on the bonnet is a stark reminder that the S 450 d is one of the best luxury cars in the world.

Best for: subtle performance

When it comes to Audi’s performance range, the RS models get all of the attention - often overshadowing the S lineup. The RS7 is a loud, rapid brute of a car, but the S7 TDI is a different beast altogether; the sleeper of the A7 range.

Audi has bucked the trend of downsizing with its diesel-powered S7, and whilst manufacturers are rushing to fit four- and six-cylinder engines to their biggest cars, Audi has stuffed a twin-turbocharged 3.0-litre V6 into its big four-door fastback. A healthy 350hp and 700Nm of torque combined with a responsive mild-hybrid, electrically-assisted turbocharger mean the S7 will break 62mph in 5.1 seconds and onto an electronically-limited top speed of 155mph.

Quattro four-wheel drive means that the S7 is sure-footed regardless of the weather, with masses of cornering grip available. That’s not to say it’s agile though, no matter how much you fiddle with the controllable driver settings.

Weighing in at almost 2.1 tonnes, the S7 does a great job of hiding its size with a sporty design. Its sporty roofline tapers all the way to the back of the car, whilst big haunches over the rear wheels and a sharp shoulder line give the S7 a more dynamic appearance than its weight would suggest on paper.

Inside the S7 has a crisp and well put-together cabin. Sporty, comfy and supportive quilted seats are the cherry on top of a high-class interior, with a solid feeling dashboard and aluminium or carbon fibre trims to hint at the S7’s sporting credentials.

The driver gets a 12.0-inch digital display, whilst the centre console and dash are home to a pair of screens; a 10.0-inch infotainment display and a 9.0-inch control screen for the air con and seat settings. They are a little fiddly though, and buttons are definitely easier to use.

A 525-litre boot with a liftback tailgate means loading and unloading bigger items is a doddle, but if you need space for big, boxy items which the S7’s roofline won’t allow then the S6 Avant is available. It’s the same car underneath, just with a less swoopy design and a big estate boot.

Best for: pretty much everything

It may be surprising that the fourth fastest diesel car on sale in the UK is a family-favourite SUV, but with leaps in engine technology and performance figures it’s little wonder that the gap is closing to smaller alternatives.

The BMW X5 introduced the very idea of a performance-oriented, luxury SUV when it was launched in 1999. BMW was very much still in its ‘Ultimate Driving Machine’ phase after all, and ever since then the X5 has maintained that reputation.

The xDrive 40d model has a 352hp inline-six engine under the bonnet, with 720Nm of torque and a 12hp electric boost. With a 0-62mph time of 5.5 seconds, the X5 betrays its size with how quickly it can accelerate and tackle twist roads. All the while it returns around 37mpg according to official tests.

Being a BMW it’s also genuinely fun to drive when the road gets twisty, especially in sport mode which sharpens up the driving controls. The X5’s interior is a well-sorted and luxurious place to be. Premium materials and a slick dual-screen set up shine, but the X5 has kept buttons for the air-con and audio which make them nice and simple to operate.

The X5 is a handsome car on the outside too, with strong, defined lines and kidney grilles which have managed to avoid the crazy-oversized treatment of some BMWs of late. All of this plus a gargantuan 650-litre boot capacity mean the X5 is a rather adept family bus, though if you’re after a sleeker design the BMW X6 xDrive 40d is the one to go for.

Best for: interior luxury

Whilst the GLE 450 d’s smaller and lighter E and S-Class siblings are quicker when powered by the same engine, what’s surprising is that at nearly two and a half tonnes the GLE manages to be as quick as it is.

The inline-six 3.0-litre engine and mild-hybrid system combine to produce a total of 390hp and 750Nm of torque - taking the GLE 450 d to 62mph in 5.6 seconds. Fuel economy does suffer as a result of the extra weight though, and the GLE only manages a combined efficiency of around 35mpg.

That being said, what it loses in efficiency the GLE makes up for in space and comfort. Whereas the BMW X5 is sportier and sharper, the GLE is curvier and more luxurious in its design. Softer edges and a more rounded shape mark the GLE out as a Mercedes, and the same applies to the interior.

Much like the S-Class, there’s leather and wood almost everywhere you look and touch in the GLE. Modern design touches do break it up however, with interesting vents and two large curved screens - one infotainment and one driver’s display.

The seats are super comfy and the steering is light, making it a doddle to drive around town and comfortable over long motorway distances. It may not be as quick or easy to park as its smaller E-Class cousin, but if you value a high driving position the GLE is a better choice, in either boxy SUV or Coupe forms.

Best for: turning heads

The Range Rover Sport has always been something of an oxymoron when it comes to SUVs. How can a Range Rover be sporty? Well, with some trick suspension settings, a sleeker design and a powerful engine under the bonnet, it turns out.

A 3.0-litre, 350hp inline-six turbocharged engine lies underneath the Range Rover Sport’s tall bonnet. With 700Nm of torque and four-wheel drive, the near-2.5-tonne SUV cracks 62mph in 5.8 seconds and on to a top speed of 145mph. For such a heavy car with a square shape, the Range Rover Sport D350 returns a surprisingly good combined MPG of around 38mpg in part thanks to its mild-hybrid system.

On a twisty road the Sport isn’t quite on par with alternatives such as the BMW X5 and Porsche Cayenne, but it’s still fun to drive - so long as you’re not pushing it too hard. It’s somewhere in the handling/comfort sweet spot; not as comfy as a ‘full fat’ Range Rover but still better on a cruise than some other options.

Range Rover styling is well renowned at this point, and the current generation Sport model is a more dynamic evolution of the classic Range Rover lines. Super-skinny headlights and new, wider taillights that carry onto the tailgate mean the Range Rover Sport is more distinctive than ever.

Inside is also an evolution of classic Range Rover design, though with a fit and finish a cut above the current Sport’s predecessors. A swish new infotainment system, comfy seats and a massive 835-litre boot make the Sport a stylish and practical SUV choice.

Best for: executive travel

Breaking up the sea of SUVs is the Audi A8 50 TDI - Audi’s quick diesel answer to Mercedes’ venerable S-Class. It’s not as quick as the Audi S7, but the A8 is the flagship luxury model of Audi’s range - a car to be wafted about in, not to hustle.

Though with a 3.0-litre V6 producing 290hp and 60Nm of torque, the A8 50 TDI can still get to 62mph in 5.9 seconds and on to a top speed of 155mph. Not too shabby for a two-tonne limousine, though it’s definitely not an agile RS model.

It’s still fun in the corners thanks to its adjustable air suspension, and it doesn’t feel as large as its dimensions suggest on paper. The A8 really shines on the motorway and around town though, where that suspension irons out bumps and imperfections in the road’s surface.

The S-Class still has it beaten on road noise, but not by much - and the cabin in the A8 is a fantastic place to be. A triple screen setup dominates the dashboard, with the centre pair controlling infotainment and climate control. The third screen is the driver’s display, but tech aside the cabin is full of old-school luxurious leather - and the seats are very plush. The boot is smaller than the S-Class though at only 505 litres.

On the outside the A8 isn’t quite as cohesive as its alternatives, and though it’s an elegant piece of design the front grille is just a little too brash and blocky. The rear light bar is a lovely touch however, and there’s no denying that the A8’s front end is menacing.

Best for: a fun-to-drive seven seater

Though it may not look it, and you may not want to look at it, BMW’s enormous seven-seater X7 is a far better car to drive than you’d think. Its tank-sized body still descends from sporty genes, after all.

Powered by the same twin-turbocharged 3.0-litre engine as the X5 M40d, the X7 produces 352hp and 720Nm of torque - though it only manages 0-62mph in 5.9 seconds. That’s still very sprightly for what is effectively a three-bed house on wheels.

It’s not just in a straight line where the X7 performs though - it really is fun to drive on a twisty road, so long as it’s not so narrow that you feel claustrophobic. In fact it’s the X7’s size which is its double-edged sword. It just feels far too big for some country lanes and city streets, but it’s a comfortable place to sit.

The dashboard is topped by BMW’s dual-screen setup with lashings of leather, metal and piano-black trim wherever you cast your eyes or fingertips. The X7 has two folding seats in the boot - comfortable for adults on a long drive. With the seats stowed away, the X7 has a cavernous 750-litre boot capacity.

When it comes to the exterior though, the X7 is less cut and dry. However, if you’re a fan of big, bold and brash designs then the X7 might be right up your alley.

Best for: opulent wafting

It’s safe to say that at this point the Range Rover is pretty far removed from its rugged roots. That’s not to say that it’s not a serious off-roader anymore - it’s better than ever in that respect - but it’s a super-luxurious city prowler these days. It’s pretty quick too.

Available with the same D350 engine and drivetrain as its smaller Sport sibling, the Range Rover is a little slower thanks to the extra weight it’s hauling around. This is by far the heaviest vehicle on this list, but the Range Rover still hits 62mph in 6.0 seconds thanks to 350hp and 700Nm of torque.

Even though it’s quick, Range Rovers aren’t best-suited to carving through B-road bends and flying out of corners. At over five metres long and two metres wide, the Range Rover is a very large vehicle.

That means it’s a fantastic place to be for its occupants, with plenty of head room both front and rear. You can even specify the long-wheelbase Range Rover with seven seats should you need to ferry six passengers around in comfort.

The interior quality is very high too, with luxurious materials almost everywhere you look and touch. A new, wide infotainment display seemingly hovers above the leather-trimmed dashboard, with real buttons for the climate control panel underneath it.

The Range Rover’s exterior is a triumph too, super sleek compared to previous generations and with some slick details such as the ‘hidden’ taillights and pop-out door handles. It’s about as swish as you can get in a modern SUV.

Best for: road presence

The Q8 is Audi’s top-of-the range SUV; a Q7-based luxury coupe-SUV which just so happens to be related to the Lamborghini Urus and Bentley Bentayga under the skin. The Q8 doesn’t cost as much, but that’s not to say it’s a worse car than its mega-posh cousins.

In 50 TDI form, the Q8 is powered by a 3.0-litre V6 with 282hp and 600Nm of torque. That may be less than a lot of the alternatives on this list, but it’s still enough for a 0-62mph time of 6.1 seconds.

It’s a very aggressively-styled car, with angry headlights and a shouty grille at the front and bulging wheel arches on all four corners. The Q7 is hardly a wallflower, but the Q8 turns its road presence up to 11 and beyond. The sloping roofline makes the Q7 look genuinely sporty too, leading into a sharp rear end.

Even with a low roofline, the Q8 is capacious inside. Four adults will fit in comfort, though the tallest of the tall might feel a little snug in the back. Front occupants get the same triple-screen infotainment as the A8 executive limo, and the cabin is just as solid to the touch as it is easy on the eye.

It’s not a race car by any means, but Quattro four-wheel drive and enormous tyres give the Q8 a super sure-footed feel, even on twisty roads in rubbish weather.