The next-generation Mazda MX-5 will be re-engineered as a lightweight, sub-one tonne two-seater, most likely powered by a down-sized petrol engine.

"The next MX-5 needs to be much lighter," said program manager Takao Kijima. "And we also need to get CO2 levels down to the B-car [Mazda 2] level."

Kijima said the next MX-5 must weigh less than 1000kg, a cut of around 120kg compared to today's 1120kg car. That's a similar weight to the original MX-5, which weighed in at 945kg.

Mazda's target is a 10 per cent "minimum" weight reduction, which will also apply to all of its new models from 2011.>> Read more on the Mazda MX-5

The MX-5 will stick with its front-engine/rear-drive layout and a steel body and platform. "Alloy is out of the question, as it's too expensive," said Kijima.

Mazda is also targeting a dramatic reduction in tailpipe emissions of carbon and is aiming for 120g/km, a 40g/km cut on today's 160g/km.

As well as the weight saving, more efficient engines are part of Mazda's plan. "I am sure a downsized engine will be necessary," said Kijima.

That most likely means 1.6 and 1.8 engines in place of today's 1.8 and 2.0 units, although it could also mean a highly efficient, possibly turbocharged, 1.4-litre unit.

Julian Rendell