Watch: Lord Ashdown backs Shropshire and Mid Wales pylons campaigners

He said while his party was in favour of renewable energy sources, it shouldn't come at the cost of the beauty of the countryside.

"The greatest asset of a beautiful constituency like Montgomeryshire, or an area like Shropshire, is nature, and the beauty of this area is why people love it. So it would be stupid, I think, if you built pylons across it," he said.

"Windfarms are important, but equally so are making sure you bury the cables and don't have a forest of pylons across the countryside.

"Our case is that we're looking at the future but we don't want to do it at the cost of the destruction of nature."

Lord Ashdown was in Welshpool last night to meet Lib Dem Montgomeryshire parliamentary candidate Jane Dodds and local party members, who have launched a No More Pylons petition.

His visit came just two weeks after current Liberal Democrat leader and Deputy Prime Minister Nick Clegg visited Berriew, near Welshpool, to give his support to Mrs Dodds's pylons campaign.

But the party is also keen to look at ways to get the most from renewable sources, Lord Ashdown said.

He said: "Renewable energy is something that the UK leads the work on in some areas to tackle climate change.

"I suspect this is the greatest challenge of a material and practical issue that we're now facing."

Mrs Dodds said her campaign is not calling for the connection project to be abandoned, but for National Grid to look at options other than pylons.

"We're keen to look at burying the pylons if they proceed," she said.