Mr Charles Kennedy said yesterday his party offered a genuine commitment to green principles, as he visited a conservation project in Kent.
"The environment is very much our issue," said the Liberal Democrats leader, who gave a helping hand to workers building a fence. "We have been described by Friends of the Earth as by far the most environmentally friendly."
His party's manifesto committed companies and government to green audits and contained detailed environmental plans in each chapter. He aimed to highlight those commitments with the visit to Scadbury Park, near Orpington, Kent.
The Liberal Democrats peer, Lord Avebury, took the Orpington seat as Eric Lubbock in a 1962 by-election shock. With a Tory majority of 2,952 over the Liberal Democrats in 1997, it is 13th on the party's target list this time.
Earlier, Mr Kennedy was cheered by local party activists as he arrived from London by train about 10 minutes late. He is promoting the party's transport and environmental plans as a package and said the Liberal Democrats would put the environment at the heart of every issue.
He was joined on the visit by the party's transport spokesman, Mr Don Foster, and his partner, Ms Sarah Gurling.
Commenting on Mr Kennedy's claim that his party was committed to green principles, the Tory environment spokesman, Mr Damian Green, said: "This is breathtaking hypocrisy from Mr Kennedy. His party's representatives on both the South East and South West Regional Assemblies have actively supported the Government's housebuilding targets and plans to concrete over our countryside."
Mr Kennedy later visited Cornwall's Eden Project. The Liberal Democrats leader was fulfilling a pledge to return to the giant biospheres made before the £86 million project was completed in March.
The environmental agenda was the political agenda of the future, and their green policies gave the Liberal Democrats a "cutting edge", he said.