First opinionIf there’s a sweet spot in the new E-Class line-up, the E220 CDI is it.While the Sport-spec model we drove previously didn’t quite hit the mark, this SE is great. It doesn’t try to be a sports saloon; instead, it majors on comfort and luxury in true Mercedes style. What’s more, it’s also very green, thanks to the firm’s clever BlueEFFICIENCY technology – mixing amazing fuel economy with strong pace. It all adds up to a classy limousine that will still appeal to loyal Mercedes enthusiasts. We’re just not convinced it will attract many new buyers to the latest E-Class family.

Meet the executive saloon that’s more economical than a Ford Fiesta! This is the Mercedes E220 CDI BlueEFFICIENCY – the latest and greenest version of the three-pointed star’s four-door limousine.

Thanks to a sophisticated 168bhp 2.1-litre twin-turbo diesel, tweaked aerodynamics and low-rolling-resistance tyres, this super-green E-Class can return 53.3mpg combined. Incredibly, that makes it 1mpg more frugal than a Fiesta 1.25.

But is the new BMW 5-Series challenger as good a luxury saloon as it is a money-saver?

One thing is for sure with the latest E-Class range: being green is in fashion. Every model in the line-up, with the exception of the petrol V8s, uses the brand’s BlueEFFICIENCY technology.

As with VW’s BlueMotion range, this combines eco-minded styling tweaks and low-drag rubber with a reduction in overall weight to help reduce fuel consumption and emissions.

As well as the headline-grabbing economy, the E220 CDI promises a remarkably low 139g/km CO2 figure. That will mean annual road tax of £120 – very impressive for such a large luxury car. It’s worth mentioning, though, that the 520d SE has slightly better returns, consuming diesel at a rate of 55.4mpg and putting out 136g/km.

How does the new E-Class stand up on the road? Well, even though this model has a green agenda and a relatively small engine, you don’t feel short-changed by the performance.

Thanks to its twin turbos, the motor offers 400Nm of torque. This arrives extremely smoothly from 1,400rpm, and translates into strong response from a standstill and an 8.6-second 0-62mph time.

Although it’s not as punchy as the more powerful E250 CDI, this model still has plenty in reserve for overtaking and, what’s more, it’s relaxed at high speeds.

The diesel engine rumbles at start-up and under hard acceleration, but cruising refinement is excellent, with minimal road or wind noise.

The good news continues when it comes to comfort. Our E220 CDI SE had a softer suspension set-up than the Sport versions we’ve driven before, and is all the better for it.

The finely judged ride soaks up bumps with ease, but keeps body roll in check when cornering. In short, it feels every inch the relaxing and luxurious large Mercedes.

It doesn’t have the BMW’s handling composure, or the same steering feel, and there is a fair degree of kickback through the overly large wheel, too.

But it’s still good to drive, and if you want a great long-distance companion, this E-Class makes real sense.

Inside, the cabin provides plenty of space for passengers and their luggage. And while the interior design is far from exciting, the upmarket materials and solid feel throughout confirm that Mercedes has worked hard on quality.

The COMAND control system, which lets the driver tweak the stereo and sat-nav settings, is not so impressive, and feels dated next to BMW’s iDrive and Audi’s MMI set-ups.

Plus, while Mercedes has tried to modernise the exterior with new headlights and tail-lamps, it’s not a great leap forward.

Even so, you can’t help but admire the way the firm has combined all those much-loved Mercedes attributes with bang-up-to-date efficiency. This is one of the best models in the new E-Class range.

Rival: BMW 520d SE
There’s not much between the 520d and the latest E-Class.

At £27,430, it’s similarly priced and very economical.

For keen drivers, its dynamic chassis will be enough to swing a purchase.