The Liberal Democrats’ attempt to mount a fightback before next May’s election has suffered a double blow as their supporters switch to the Greens and Ukip.

The Independent’s latest “poll of polls” reveals that 12 per cent of people who voted Lib Dem in 2010 intend to vote Green and another 9 per cent are backing Ukip. These losses are on top of the 30 per cent of Lib Dem voters who have switched to Labour,.

More recent losses to the Greens and Ukip explain why the Lib Dems languish in single figures in the “poll of polls”. Mr Clegg’s party, which won 23 per cent of the vote at the last election, is stuck on 9 per cent, trailing Ukip (13 per cent), the Tories (32 per cent) and Labour (35 per cent). The Greens are on 6 per cent, boosted by ex-Lib Dem voters since the spring.

The losses to Ukip are more surprising, given its anti-EU stance and the Lib Dems’ support for EU membership.

John Curtice, professor of politics at Strathclyde University, who compiled the “poll of polls,” said that if the Lib Dems gained only 9 per cent of the vote, it would be their lowest share since 1974.