Lib Dems insist they're still their own party – but poll shows voters disagree

The Liberal Democrat president, Tim Farron, tore into the party's Conservative coalition partners as he ruled out any suggestion of an electoral pact in 2015.

He even suggested that the party could walk out of government before then. Mr Farron, seen as a potential successor to Nick Clegg, joked that the image of the Coalition Government as a marriage was depressing.

"If it's a marriage, well, its a good-natured one, but I'm afraid its temporary," he told the conference. "I don't want to upset you, and it's not going to happen for three or four years, but I'm afraid divorce is inevitable."

He repeatedly praised Mr Clegg's leadership, saying he "stood up against reactionary Tory drivel after the riots". Mr Farron urged the party not to be downhearted by poor opinion-poll ratings, insisting: "We've got nerves of steel. Survival is what we do."

The uphill task facing the party to rebuild popularity is illustrated today by The Independent's latest "poll of polls". It suggests that Mr Clegg's strategy of distancing the Liberal Democrats from the Conservatives has failed to improve his party's standing with the public.

Since the Lib Dems suffered heavy defeats in the May council elections and referendum on the voting system, Mr Clegg has trumpeted his party's "gains" inside the Coalition more loudly. But the Lib Dems' average poll rating is stuck at 13 per cent, exactly where it stood in February, March and April.

"There is little sign that this new approach is helping the party or Mr Clegg to repair the extensive damage the first 12 months of the coalition did to their reputation," said John Curtice, professor of politics at Strathclyde University, who compiled the "poll of polls".

He added: "Sniping at the Conservatives from the sidelines looks as though it will not be enough to bring back into the fold those voters who feel some of the decisions to which the Liberal Democrats were party in the Coalition were at odds with the promises they made in the election campaign."

Mr Clegg's personal ratings are "no better now" than they were in April. He remains more unpopular than David Cameron and Ed Miliband. The "poll of polls", based on a weighted average of surveys taken by ComRes, ICM, Ipsos Mori and YouGov, puts Labour on 39 per cent, the Conservatives on 36 per cent, the Lib Dems on 13 per cent and other parties on 12 per cent.