Kennedy's people throw their weight behind Chris Huhne

Charles Kennedy's closest aide is backing Chris Huhne as the next Liberal Democrat leader, saying he is "best placed to take on Cameron".

In the strongest indication yet that Mr Kennedy is privately supporting Mr Huhne as his successor, his former chief of staff, Lord Newby, said he has the "high levels of energy" required to be leader and the policies to see off the Tory threat. His comments will be interpreted as a veiled attack on Sir Menzies Campbell, who is 64.

Lord Newby said Sir Menzies "will find the marathon hard going. Being leader of the Liberal Democrats requires consistently high levels of energy, and Chris has that," Lord Newby told The Independent on Sunday.

The intervention of Lord Newby will be a harsh blow to Sir Menzies, who is acting leader. It comes after the Liberal Democrats won a stunning by-election victory over Labour in Dunfermline and West Fife last week. The victory has been credited to Sir Menzies' insistence that he campaign there every week and his call for Liberal Democrat MPs to join him.

But Lord Newby said the by-election win strengthened the case for Mr Huhne to become leader because it illustrated the need for coherent domestic policy - Mr Huhne's strength.

"I have decided to come out of the closet in this contest - and the Dunfermline result reinforces my support for Chris Huhne. We need a leader who can take Labour on on heartland issues. Chris Huhne has done well in the media spotlight," he said.

Mr Kennedy, who resigned last month after admitting he had an alcohol problem, has said he is neutral in the campaign, but he is understood to be in frequent contact with Lord Newby. The peer's comments will be interpreted as an indication that Mr Huhne, aged 51, has Mr Kennedy's backing.

A YouGov poll of Lib Dem members last week put Mr Huhne on 38 per cent, Sir Menzies on 34 per cent and Simon Hughes on 27. The poll suggested that Mr Huhne would eventually defeat Sir Menzies by 52 per cent to 48 per cent.

However, a poll today for The Sunday Times put Mr Hughes well ahead among Liberal Democrat supporters on 34 per cent, followed by Sir Menzies on 21 per cent and Mr Huhne trailing on 13 per cent. Allies of Sir Menzies expressed confidence that he is still in pole position to be elected Lib Dem leader. "Our figures show we are ahead and we are working hard to win every vote," said a spokesman for the Campbell campaign.