Nick Clegg tells Lib Dems: Have courage and stick with coalition
Nick Clegg has urged the Liberal Democrats to show "courage and vision" in making the coalition work, arguing his party has not been "found wanting".
In his end-of-conference speech, the leader said members faced making a choice between "protest" and "power".
Mr Clegg also announced that former leader Lord Ashdown would become the Lib Dems' elections planning supremo.
Amid low poll ratings and reports of disillusionment, he told supporters their pain would be "worth it".
A recurring theme of the week has been Mr Clegg's apology about the party's failure to fulfil its pre-election promise to fight any increase in university tuition fees after entering government with the Conservatives.
Mr Clegg's 37-minute speech will be seen as an attempt to re-emphasise the importance of the Lib Dems' influence at Westminster.
The slogan of the conference, in Brighton, has been "fairer tax in tough times", with minister after minister standing up to portray themselves as voices of moderation and social mobility within government.
With this theme in mind, Mr Clegg said there could be "no question" of further lowering the top income tax rate of 45%, which will come into force next April, "in this Parliament". The current top rate is 50%.
The deputy prime minister also announced an extra £500 each for 110,000 of England's worst-performing 11-year-olds to help with the transition from primary to secondary school.
He said: "If you're a parent whose child has fallen behind, who fears they might get lost in that daunting leap from primary to secondary school, and who is worried by talk about making exams tougher, let me reassure you: we will do whatever it takes to make sure your child is not left behind."
Some opinion polls put the Lib Dems' level of support below 10%, with several Conservative MPs accusing the party of wanting to move away from the coalition's commitment to cutting the budget deficit.
Yet Mr Clegg rejected that criticism, saying that "we've stuck to our task - and to the coalition agreement - even as others have wavered".
"The received wisdom, prior to the election, was that we wouldn't be capable of making the transition from opposition to government," he said.
"The choices would be too sharp, the decisions too hard. The Liberal Democrats, it was said, are a party of protest, not power.
"Well, two years on, the critics have been confounded. Our mettle has been tested in the toughest of circumstances, and we haven't been found wanting."
He said the party should avoid taking "the populist side", saying the "big prizes are for those with the courage and vision to get out in front, set the agenda and point the way".
Mr Clegg revealed that Lord Ashdown, who led the party from 1988 to 1999 and is popular among many activists, would oversee strategy in the lead-up to the 2015 general election.
He said: "I can't think of anyone I'd rather have by my side."
Addressing the future, Mr Clegg said the Lib Dems faced two "journeys" - in government and as a political force - warning: "Neither will be easy. And neither will be quick. But it will be worth it. And be in no doubt. If we secure our country's future, we will secure our own."
He added: "I am proud of the resolve we Liberal Democrats have shown over the last two and a half years. We've had some real disappointments: tough election results; a bruising referendum.
"But throughout it all we have remained focused, determined, disciplined. It hasn't always been easy, and, when we've made mistakes, we've put our hands up."
Mr Clegg said: "I know that there are some in the party - some in this hall even - who, faced with several more years of spending restraint, would rather turn back than press on.
"It's an alluring prospect in some ways. Gone would be the difficult choices, the hard decisions, the necessary compromises. And gone too would be the vitriol and abuse, from right and left, as we work every day to keep this government anchored in the centre ground.
"The choice between the party we were, and the party we are becoming, is a false one. The past is gone and it isn't coming back. If voters want a party of opposition - a 'stop the world I want to get off' party - they've got plenty of options, but we are not one of them.
"There's a better, more meaningful future waiting for us. Not as the third party, but as one of three parties of government."
As part of efforts to cut spending after the next election, Lib Dem sources confirmed on Tuesday the party would look at curbing all age-related universal benefits - such as winter fuel allowances, free TV licences and bus passes - for pensioners with assets of more than £1m.
Mr Clegg's speech ended the Lib Dem conference. Labour meets in Manchester from this weekend and the Conservatives gather in Birmingham a week later.
Labour's deputy leader Harriet Harman said the speech was "pointless rhetoric... the truth is that they have betrayed the people who voted for them and far from being a brake on the Tories, they are their accomplices".