The Green Party has set out its policies for "peace, public services and the planet's resources".

Key candidates and senior party figures gathered in Westminster on Thursday for the launch of a billboard campaign that highlighted key election themes.

After criticising the transport used by the Liberal Democrat leader at the start of his campaigning on Tuesday, the Greens are keen to highlight their own environmental credentials.

The party said that Charles Kennedy's use of an aeroplane to travel around the UK would release 100 tonnes of CO2 into the atmosphere.

So the Green candidates opted for a suitable alternative, towing the billboards back to their constituencies on bikes.

Keith Taylor, one of the Green's principal speakers, said the party was "fighting this election on an unashamed platform of social, economic and environmental justice".

The plans would put "peace, public services and the planet's resources at the heart of our policies".

And they would provide "a choice for real change from the business as usual politics of pollute and privatise", he added.

The launch of the party's detailed manifesto follows next week.