Seat might be the ’sporty’ Volkswagen Group brand, but it’s also fast becoming known for its green Ecomotive models, marketed with the tag line ‘less emissions, more emotions’.

As a new Seat Leon Ecomotive heads for showrooms, Andy Goodwin drove it with the lightest of right feet at its birthplace, just outside Barcelona.

The outgoing Seat Leon Ecomotive was a seriously clean and efficient family hatchback. Its 1.9-litre turbocharged diesel engine would easily return more than 50mpg on a run and its official emissions of 119g/km made it cheap to tax.

Now Seat has raised the bar even higher and given customers a more tempting alternative to conventional diesel cars including the Volkswagen Golf Bluemotion and Ford Focus Econetic as well as hybrids like the Toyota Prius and Honda Insight.

Emissions of 99g/km and an official fuel consumption of 74.3mpg make it free from annual road tax and mean a driver with an average annual mileage should need to visit the pumps less than once a month.

With its standard 55-litre fuel tank 900 miles is possible between refills, so saving for treats with your fuel card could prove frustrating.

How is it done? The biggest change is the brand new 1.6-litre 105bhp common rail diesel engine mated to a five-speed gearbox.

This engine and the carefully-chosen longer gears reduce CO2 emissions by 9g/km compared with the 1.9-litre Ecomotive.

A further 8g/km are lopped off by installing stop and start technology which cuts the engine at traffic lights, and energy recovery, which uses braking forces to recharge the battery instead of an inefficient alternator.

Test the Leon Ecomotive in a Formula 1-style wind tunnel and the air whips cleanly over its body thanks to a closed front grille, 40mm front chin spoiler and wind deflectors fore and aft of the front wheels.

The aero package and low-rolling resistance tyres save an extra 3g/km all-in-all and reduce the 0.33cd drag coefficient of the standard car to a round 0.3cd.

Long gear

Driving the Leon Ecomotive doesn’t require any change of habits from the driver, but the extra-long gear ratios mean it’s easy to stall the car if you select too-higher cog.

As an aid the dashboard has a gearchange indicator which suggests the most economical gear as you drive.

Ignore it completely and the Leon Ecomotive can be goaded from 0-62mph in a respectable 11.7 seconds and on to a top speed of 117mph.

Handling-wise the Leon behaves exactly as you’d expect it to, with well-weighted steering and a controlled chassis in corners and over bumps.

The rubber compound and high air pressure of the mpg-orientated tyres rob the Ecomotive of some outright grip, but this shouldn’t worry drivers of an eco-model.

As an alternative Seat will also offer the Leon in Ecomotive Technology spec. This car benefits from the same engine, gears, stop and start and energy regeneration as the Ecomotive model, but loses the aerodynamic tweaks and special tyres.

With emissions of 109g/km it’s still more environmentally-friendly than the outgoing Leon Ecomotive, and you can have 18-inch alloys with sports tyres – making it a tempting proposition for all but the most die-hard environmentalists.

Key facts
Model tested: Seat Leon Ecomotive 1.6TDi
Date and place tested: December 2009
Road tester: Andy Goodwin