With a host of fuel-saving features, say hello to the leanest and greenest Leon

How far does one tank of fuel take you in your car? Chances are it won’t be able to match SEAT’s latest green machine, which, on a single fill, can make it from London to Barcelona – more than 900 miles.

Couple the lengthy range with reduced CO2 emissions, and this could be the SEAT that finally offers driving thrills to those with an eye on their wallets and the environment.

Badged ECOmotive, it is all about the evolution of existing engines, rather than developing new technology. As a result, there’s no electric motor or hydrogen fuel cells under the bonnet. Instead, the existing 103bhp 1.9-litre oil-burning powerplant has been tweaked for economy, and gets a revised engine management system and the latest diesel particulate filter.

Throw in a set of low-resistance tyres and a five-speed gearbox with extra-long ratios, and the result is a combined fuel figure up from 56mpg to 62.8mpg. What’s more, CO2 emissions have been slashed from 135g/km to 119g/km and weight reduced from 1,405kg to 1,320kg.

SEAT bosses are yet to confirm costs, but expect to pay more for the Leon’s green credentials. The premium could be as little as £350, or as much as £850, over the standard £13,645 1.9 TDI.

So is the new ECOmotive worth the extra? The reduction in weight shaves 0.4 seconds off the 0-62mph time and it retains the sporty character we’ve come to expect from the Leon range. In fact, it’s only the revised gear ratios that detract from the overall package. Third, fourth and fifth have all been lengthened for economy – fifth by a substantial 16 per cent. On motorways, that is a bonus, but tackle a back road, and you’ll be forced to change down. Even at 50mph, the SEAT struggles to pull in top gear.

However, on our test route in the Spanish hills, the ECOmotive averaged a respectable 52mpg, and a superb 64mpg on the open road. Ultimately, with only a sticker on the boot indicating that the model is different from the rest of the Leon range, the ECOmotive really lacks the visual cachet of Toyota’s Prius. But despite this, SEAT’s claim about its efficiency seems genuine and the frugal Leon is a sensible bet for motorists aiming to beat soaring fuel costs and do their bit for the planet.