Britain's cleanest cars - Open-top cars

What Car? Greenest Open-top car: Vauxhall Tigra 1.3 CDTi 16v

You might not expect anything as frivolous as a convertible to knuckle down and fight global warming, but Vauxhall's Corsa-based Tigra does just that.

It posts an excellent CO2 figure of 124g/km in 1.3-litre diesel guise. Low emissions bring correspondingly good fuel economy – the two-seat Tigra's 61mpg average makes it the most fuel-efficient open-top car on sale in the UK. So you'll save money at the pumps, as well as saving the environment.

Its high-tech common-rail diesel engine musters 69bhp and 125lb ft of pulling power, which ensures that the folding metal-roofed Tigra doesn't feel sluggish. It's a conscience-pleasing combination that marries open-top style with genuine green credentials.
Price: From £14,995
MPG: 61.4
CO2 emissions: 124g/km

Lotus Elise 111R
The Toyota-engined Elise is slightly less frugal than the original, but no other car capable of 0-60mph in under 5sec can also manage 32mpg. It's all down to its light weight – bulk is the enemy of fuel economy.
Price: £28,995
MPG: 32.1
CO2 emissions: 208g/km

Audi A4 Cabriolet 2.0 TDI
All the glamour of any A4 Cabriolet, but with better economy and lower emissions: that's the new 2.0-litre TDI turbodiesel model.

Carbon dioxide emissions drop to 175g/km and the combined fuel figure is now 43.5mpg, compared with 204g/km and 33.2mpg for the base 1.8 petrol.

The price is still on the high side, but the svelte four-seater now has a particulate filter fitted as standard.
Price: From £23,476
MPG: 43.5
CO2 emissions: 175g/km