Real MPG: most economical executive and luxury cars

NEDC MPG 78.5mpg | Real MPG Average 53.7mpg | Town 47.7mpg | Motorway 47.0mpg | Rural 69.2mpg

Yes, it may have gone off sale in 2022, but the Ford Mondeo – when fitted with a 1.5-litre diesel engine – remains the most economical car we've tested from the executive and luxury car classes. It’s narrowly beaten for motorway efficiency by the second-place Vauxhall Insignia, but makes up for it both on country roads and around town with better fuel economy and, we think, better driving manners.

It isn’t nearly as plush as the best executive cars, but the Mondeo offers plenty of other qualities that make it a brilliant used buy. It's good to drive, it has a spacious interior, and its large boot has a practical hatchback opening.

Read our full used Ford Mondeo review

WLTP MPG 60.1mpg | Real MPG Average 53.3mpg | Town 46.4mpg | Motorway 47.8mpg | Rural 67.2mpg

Like the Ford Mondeo above, the Vauxhall Insignia is no longer on sale as a new car, but there are a good number of examples on the used market, with prices starting from just £6000. What's more, if you look for a later model, you might find one fitted with the economical 1.5-litre diesel engine we tested here. It has a good amount of punch, although you might appreciate one of the more powerful 2.0-litre options if you regularly travel with a full car.

If you do intend to travel fully laden, you’ll be pleased to know that the Insignia offers plenty of space for passengers and a sizeable boot.

Read our full used Vauxhall Insignia Grand Sport review

WLTP MPG 53.3mpg | Real MPG Average 52.2mpg | Town 45.6mpg | Motorway 46.2mpg | Rural 67.0mpg

The Audi A4 is a former What Car? Car of the Year and impresses with class-leading interior quality, a plethora of standard equipment and the fact that all its engines are smooth.

The 2.0-litre diesel engine in the 35 TDI variant we tested has plenty of punch for most situations, and won't cost you a lot to run. The overall result we achieved with it was just 2.1% adrift of its official WLTP fuel economy.

Ride quality is impressive, with the A4 able to glide over the worst ruts and bumps while maintaining good body control. The A4 handles well, too, with precise and well-weighted steering.

Read our full Audi A4 review

NEDC MPG 68.9mpg | Real MPG Average 48.2mpg | Town 37.8mpg | Motorway 45.4mpg | Rural 61.1mpg

While it was on sale, the previous-generation Skoda Superb was one of the best-value executive cars around. It’s since been replaced with a new Skoda Superb, but there are lots of used examples of the old model to be found.

Finding a high-mileage Superb fitted with the economical 2.0-litre diesel engine featured here won't take you long, and with prices starting from just £6000, they’re affordable to buy as well as run. Ride and handling are generally good, and the Superb is impressively refined at motorway speeds.

Read our full used Skoda Superb review

NEDC MPG 68.9mpg | Real MPG Average 47.3mpg | Town 41.4mpg | Motorway 41.9mpg | Rural 60.7mpg

The Mazda 6 may be a left-field choice among executive cars, but it can hold its own against better-known rivals like the Ford Mondeo and Vauxhall Insignia. The 6 is very well equipped and pleasant to drive, and the 2.2-litre diesel engine we tested here offers flexible performance.

This version of Mazda’s executive car also returns better fuel economy than many rivals, achieving upwards of 47mpg overall in our tests and more than 60mpg on country roads.

Read our full used Mazda 6 review

WLTP MPG 57.6mpg | Real MPG Average 47.2mpg | Town 31.7mpg | Motorway 46.1mpg | Rural 65.1mpg

Before the days of plug-in hybrid and electric car tax incentives, the BMW 320d was a go-to choice among company car drivers. That means there are plenty of used examples out there and, as our real-world tests show, the previous-generation 320d is also very fuel-efficient.

Indeed, we achieved more than 46mpg on motorways and upwards of 65mpg on country roads in our tests. As with any 3 Series, it's great to drive and comfy inside – with one of the best infotainment systems you'll find in any new car at this age.

Read our full used BMW 3 Series review

NEDC MPG 67.3mpg | Real MPG Average 45.7mpg | Town 37.3mpg | Motorway 42.4mpg | Rural 57.5mpg

The Alfa Romeo Giulia is the Italian brand’s executive car offering, and it’s proven to be a credible alternative to rivals from the likes of Audi and BMW. There’s a real sense of occasion every time you get behind the wheel, and the Giulia continues to impress when you’re on the move.

Plus, if you go for the 177bhp 2.2-litre diesel engine, you'll enjoy a car that's wonderfully economical, although you'll have to look for a used example because this engine has been discontinued.

Read our full used Alfa Romeo Giulia review

NEDC MPG 67.3mpg | Real MPG Average 45.4mpg | Town 35.9mpg | Motorway 42.7mpg | Rural 57.0mpg

A used Volkswagen Passat saloon with a 2.0-litre diesel engine is a ruthlessly efficient secondhand purchase; ours returned upwards of 57mpg on the rural section of our test, and close to 43mpg on the motorway route.

Add that efficiency to the Passat's other strengths – a comfortable interior and big boot, for example – and it's a very tempting package. If you’d rather buy new, you might want to consider the current Volkswagen Passat; it’s only available as an estate car, though.

Read our full used Volkswagen Passat review

WLTP MPG 56.5mpg | Real MPG Average 45.2mpg | Town 35.1mpg | Motorway 43.2mpg | Rural 56.5mpg

Diesel-powered examples of the current-generation BMW 3 Series are a little harder to come by than those of previous models; partly because diesel has fallen out of favour with executive car drivers in recent years, and partly because you can no longer buy a new 3 Series with a diesel engine. 

If you do manage to get your hands on one, though, you’re in for a treat. The 3 Series is fantastic to drive and plush inside, and the 2.0-litre diesel engine in the 320d variant promises great fuel economy – our test car eked more than 45 miles from a single gallon of fuel.

Read our full used BMW 3 Series review

NEDC MPG 72.4mpg | Real MPG Average 44.8mpg | Town 34.7mpg | Motorway 41.4mpg | Rural 59.2mpg

The previous-generation Mercedes E-Class is the only luxury car to find its way into our top 10 and, of all the models in the class, it’s one of the best-suited to a life of motorway use. Every E-Class is comfy at speed, and all but the sportiest versions are very refined. 

The generation we tested has since been replaced with a new Mercedes E-Class, but there are plenty of used examples around. With a comfortable, high-quality interior and a decent haul of kit as standard, this E-Class remains a recommendable choice.

Read our full used Mercedes E-Class review