IoS exclusive: Cameron hit by big rise in hostility to Europe

And at the G8 summit, world leaders issue strong message calling for stimulus to encourage growth

Almost one in three people who voted Conservative at the last election are ready to back the UK Independence Party, or have switched already, according to a devastating new opinion poll revealing the danger posed to David Cameron by a growing anti-Europe sentiment across Britain.

Ten per cent of 2010's Tory voters say they have already decided to back Ukip, while 26 per cent of those who still support the Conservatives are "seriously considering" switching to support the Eurosceptic fringe party. Nigel Farage, its leader, has sought to capitalise on the economic crisis gripping the eurozone.

Forty-six per cent of people polled say they would vote for Britain to leave the European Union, with just 30 per cent saying they want to continue membership. If the 23 per cent who responded "don't know" were removed, such a referendum would see Britain leave the EU on a 3:2 split.

The results will heap pressure on Mr Cameron, who faces demands from his backbenchers and ministers for a referendum on continued membership in the next Tory manifesto. But a more strident anti-European stance will do little to improve the Prime Minister's international standing. Yesterday, he joined world leaders for talks at Camp David, where efforts were being made at the G8 to encourage growth as well as austerity.

With little sign of a breakthrough in efforts to rescue the Greek economy – and, with it, the eurozone – Mr Cameron again resorted to hyperbolic rhetoric to reassure increasingly sceptical voters back home that he was having some impact on the world stage. Speaking after holding bilateral talks with President Barack Obama yesterday morning, Mr Cameron declared: "There is a growing sense of urgency that action needs to be taken, contingency plans need to be put in place and the strengthening of banks, governance, firewalls, all of those things, need to take place very fast."

German Chancellor Angela Merkel's agenda for Europe, demanding ruthless austerity to tackle national deficits, was under assault. The new French President, François Hollande, allied himself to President Obama's policy of investing to stimulate economic growth. "All of us," Mr Obama said, "are absolutely committed to making sure that both growth and stability, and fiscal consolidation, are part of an overall package to achieve the prosperity for our citizens we all are looking for."

Ms Merkel was on the back foot even before arriving at Camp David, as patience with the tough-love German approach ebbed away. It was this tactic that had helped fuel a voter rebellion in Greece and set the stage for the political transition in France, where President Hollande took power on a pledge to put new emphasis on stimulative economic measures.

There was a sense of alarm among leaders of the G8 nations – the United States, France, the United Kingdom, Germany, Japan, Italy, Canada and Russia – that the renewed strains in Europe are threatening to bring back a fresh period of recession that could quickly infect all of their economies.

A statement from G8 leaders mentioned "growth" no fewer than 10 times. It began: "Our imperative is to promote growth and jobs" and included phrases such as: "We all have an interest in the success of specific measures to strengthen the resilience of the eurozone and growth in Europe". Direct references to Merkel-style austerity numbered three, however. Meanwhile, the leaders did not actually identify individual steps that might stimulate the EU economies. Those may come, however, at what should be a more consequential EU summit next week.

Mr Cameron's only mentions of the G-word were when he insisted: "Growth and austerity aren't alternatives. You need a deficit reduction plan in order to get growth, in order to have the low interest rates that we have in Britain." But he knows the coalition's cuts programme leaves him increasingly isolated on the world stage, with Tory backbenchers demanding a tougher line on Europe to head off the haemorrhaging of support to Ukip.

Mr Farage said: "The only people who can possibly be surprised by this poll are the Tory leadership, whose head has been in the sand for such a long time, both on the growth of Ukip and the party's absolute dissatisfaction at their own leadership on this massive issue."

The ComRes/IoS poll reveals deep dissatisfaction with the mainstream parties, with 37 per cent of their supporters seriously considering switching to smaller parties. Among all voters polled, 13 per cent are pondering backing Ukip, with the same proportion poised to vote Green. Four per cent are considering supporting the BNP, and 3 per cent could vote for George Galloway's Respect party. Only 38 per cent are not considering changing their allegiance.

Overall, Labour now has a nine-point lead, on 41 per cent, up two points on the last ComRes poll. The Tories are on 32 per cent, down two points. The Liberal Democrats are up one point, on 11 per cent; Ukip is down two points, on 7 per cent; and the Greens are up one point, on 3 per cent.

Among Labour voters, the disaffected are most likely to be looking to the Green Party (19 per cent), Ukip (11 per cent) or the Lib Dems (10 per cent). Of Lib Dem supporters, 28 per cent are considering switching to the Greens, 27 per cent to the Conservatives, 21 per cent to Labour and 14 per cent to Ukip.

But Conservative Central Office will be most concerned by the revelation that a third of its 2010 support could disappear to Ukip. The Tory MP Stewart Jackson said: "There is a growing realisation within the leadership of the Conservative Party that Ukip could potentially cost us any chance of having an overall majority at the next election, in 2015."

However, the Tory MP Brandon Lewis warned colleagues against taking a more hardline eurosceptic stance. "We mustn't be tempted to lurch in one way or the other," he said.

Voters are also becoming increasingly dissatisfied with Mr Cameron's performance. Yesterday, Downing Street played down reports of the PM's laid-back approach, after a new book quoted an ally as saying: "If there was an Olympic gold medal for 'chillaxing', the Prime Minister would win it." The biography of Mr Cameron, by James Hanning, deputy editor of The Independent on Sunday, and Francis Elliott of The Times, also revealed how Mr Cameron unwinds at Chequers with a karaoke machine, plays tennis against a machine nicknamed "the Clegger" after the Deputy Prime Minister, and enjoys a few glasses of wine with Sunday lunch.

Mr Cameron's net approval rating – the difference between those who say he is doing well and those who disagree – is down seven points to minus 28. He has been overtaken by Ed Miliband for the first time since ComRes began asking the leadership questions in December 2010. Even among Tories, just two-thirds (67 per cent) of Conservative voters say Mr Cameron is turning out to be a good prime minister, down from three-quarters (75 per cent) in April. And Mr Cameron and George Osborne are now neck-and-neck, on minus 29 per cent, with Mr Miliband and Ed Balls on being trusted to make the right decisions about the economy.

PM's iPad reshuffle

Which cabinet minister is a watermelon? Eric Pickles? Michael Gove is probably a strawberry.

This will all be terribly important when David Cameron starts hacking through his top team with his (metaphorical) samurai sword. The Prime Minister has said the iPad game, Fruit Ninja, is a good substitute for a reshuffle: "It's quite good, to get your frustration out."

According to Fraser Nelson, editor of The Spectator, the PM "spends a crazy, scary amount of time playing Fruit Ninja". You score points by dissecting melons, pears, strawberries, mangos, oranges, lemons and coconuts as they fly into view.

But beware: bombs with lit fuses pop up – slice one of them and, like an attempt to oust George Osborne or William Hague, the results are explosive. In fact, it's game over.

Matt Chorley