A NEW engine is set to turn the latest version of the Lotus Elise into the cleanest high-performance sports car in the world.

Thanks to an advanced 1.6-litre motor, exhaust emissions are cut to just 155g/km to give the popular British two-seater model the lowest CO2 rating for any petrol-driven sports model.

But clever combustion technology also allows the 124mph Elise to boast average economy of 46mpg - a spectacular 23 per cent improvement over its predecessor.

Despite being 200cc smaller than the engine in the outgoing Elise S, the new motor has a similar power output and zips the car to 62mph from rest in 6.7 seconds.

It also gets a new six-speed close ratio gearbox as part of revisions that will give the three-car range face lifted bodywork, new design wheels and three-year warranties when it goes on sale in April.

With its 1.8-litre motor, the 192PS Elise R reaches 138mph and the 220PS supercharged SC version has a top speed of 145mph. Prices will be announced later.