Blow for Nick Clegg as poll finds Vince Cable is preferred as Lib Dem leader Meanwhile Norman Lamb, the party's health minister, signalled in a Sunday Telegraph interview that senior Lib Dems would fight moves by Mr Osborne to introduce regional variations in public-sector pay - one of the Chancellor's flasghip policies as he looks to curb the public wage bill. There are some grounds for optimism for the Lib Dems in today's ICM poll, which sees their projected share of the vote at the next general election increase by one point from last month to 18 per cent - a higher figure than they achieve in most surveys. Overall the "Wisdom Index" poll - which asks voters to predict the next election result rather than which party they support - puts Labour on 37 per cent, and the Tories on 31 per cent. Labour's lead is cut by one point from last month. When asked whose leadership would attract most voters to the party, 21% of all those polled picked Mr Clegg, with 32% identifying Mr Cable, the Business Secretary. New evidence of the Business Secretary's popularity emerges amid reports this weekend that Ed Miliband, the Labour leader, would be prepared to make Mr Cable the Chancellor in a possible coalition between the two parties after the 2015 General Election. Such a move might be popular with some voters - but overlooking the shadow chancellor, Ed Balls, would risk igniting a damaging row within Labour's ranks. Mr Clegg and other senior Lib Dems aim to use their party conference to announce a series of policies in a bid to revive the spirits of his coalition-weary troops. The party has been overtaken by the UK Independence Party (UKIP) in some polls, and Lib Dem membership has fallen below 50,000 for the first time. In an attempt to enthuse the party faithful, and mark out diving lines with the Tories, the Deputy Prime Minister yesterday repeated his call for new taxes on those "sitting on a fortune." While some Tories are calling for further public spending cuts before the General Election, Mr Clegg is pushing for an emergency tax "on unearned wealth" such as a mansion tax. Last night senior Lib Dem sources said that Mr Clegg will seek to block any additional spending cuts planned after the current spending review finishes in April 2015 if the Coalition does not introduce a new wealth tax. Meanwhile, David Laws, the schools minister who returned to Government in the recent reshuffle, yesterday announced a boost to the pupil premium, a flagship Lib Dem policy which gives schools extra funds if they have children from poorer backgrounds. Mr Laws said the annual level of funding for each pupil will rise from £600 to £900 a year from 2013, with a further increased planned for the following year. Meanwhile, Mr Lamb announced plans to provide an extra £100million to build accommodation for the elderly. The new funding will finance the building of around 3,000 homes with kitchens, bathrooms and other fittings designed to allow the frail and infirm to continue to live at home rather than go into a care home. The policy will also be billed as a policy to stimulate economic growth as it will offer some support to the depressed construction industry. Mr Lamb also said that the Lib Dems would try to step up their independent voice in Government over the coming months, adding that senior figures in the party would look to oppose one of George Osborne's flagship policies to curb public sector pay. The health minister and close friend of Nick Clegg, urged the Chancellor to be "very cautious" about trying to impose regional variations in public sector pay. The Chancellor announced plans to end national pay bargaining for civil servants, NHS staff and other public sector workers in the Budget earlier this year. He hopes that regional pay rates would help slash wage bill of six million public sector workers at a time when the Government is struggling to keep its deficit reduction plan on track. "This is already a period of real anxiety for many people," said Mr Lamb. There are many individuals who are doing important work in the public sector who have already taken a hit on their pensions and endured a two-year pay freeze. Mr Lamb said he was "open-minded" about the prospect of forming a coalition with Labour after the 2015 election. Last night Mr Clegg used his opening conference speech to attack Conservative backbenchers for undermining the Coalition by trying to force through a "turbo-charged" Right-wing agenda. My message to them is: You didn't win the last election. You do not have a majority," Mr Clegg said. The British people have not given you the right to act like you do. We formed this Coalition in good faith and for the good of the country at a time of crisis. This required compromise on both sides. Liberal Democrats have kept our side of the bargain. You must too. Mr Clegg was last night announced that Danny Alexander, the Lib Dem Chief Secretary to the Treasury, is to lead a Government review to find a cheaper alternative to Trident, Britain's ageing nuclear deterrent.