No more apologies: Nick Clegg sets out his plan to stay in government

Leader targets wealthy pensioners ahead of speech designed to give party long-term vision

Nick Clegg will today tell his Liberal Democrat critics it is too late for the party to turn back to the comfort zone of opposition and insist it is on course to become "one of three parties of government".

In his closing speech to the Liberal Democrat conference, he will warn the country that it still faces a long, hard journey from "the sacrifices of austerity" – and several more years of spending cuts – to "the rewards of shared prosperity". He will say his party is on an interlinked journey "from the comforts of opposition to the hard realities of government".

Yesterday, Mr Clegg insisted he was the right man to lead his party at the next election, following his personal apology last week for the party's broken manifesto promise on student fees. But there is speculation at the margins of the Brighton conference that he could come under pressure to stand down if the Liberal Democrats' poor opinion poll ratings do not improve.

The Deputy Prime Minister said some cuts to the welfare budget were inevitable and made clear he would support withdrawing winter fuel payments and free television licences and bus travel from wealthy pensioners.

David Cameron has ruled out such a move before 2015 because he pledged at the last election to maintain the benefits. But Don Foster, the Liberal Democrat Communities Minister, told BBC Radio 5 Live: "If we can get something like this implemented now that would be better."

Mr Clegg will use today's speech to announce a £55m scheme to provide help such as one-to-one tuition to 110,000 children who have fallen behind on English and maths in primary school so they can catch up when they start secondary school. The new "catch-up premium" will provide £500 for every pupil who leaves primary school without reaching the expected level in the two subjects. "We're raising the bar, but we're ensuring every child can clear it too," Mr Clegg will say.

He will tell Liberal Democrats who want to pull out of the Coalition and pose as "a party unchanged" at the 2015 election there can be no turning back. He will admit: "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."

But he will insist: "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."

Referring to parties such as the Greens and Ukip, Mr Clegg will add: "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." The Liberal Democrat leader will declare that he is "proud" of the resolve his party has shown.

He will say: "It hasn't always been easy, and, when we've made mistakes, we've put our hands up. But we've stuck to our task – and to the Coalition Agreement – even as others have wavered."

He will argue: "The received wisdom, prior to the election, was that we wouldn't be capable of making the transition from opposition to government. 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."