Cameron aims to end lurch right and show off compassionate side

Cameron watched Boris Johnson's speech earlier today (Getty Images)

David Cameron will insist today that he has not abandoned "compassionate Conservatism" as he argues that spending cuts and welfare reform will be good in the long run for the poor, weak and vulnerable.

In his closing speech to the Tory conference, the Prime Minister will seek to reclaim the One Nation banner from Labour. He will also issue a stark warning that Britain could be left behind unless "difficult and painful decisions" are taken.

"Britain may not be in the future what it was in the past because the truth is that we are in a global race today and that means an hour of reckoning for countries like ours – sink or swim, do or decline," he will argue. A key theme of his speech will be to position the Tories as on the side of the "strivers" who work hard to achieve their aspirations.

Yesterday Mr Cameron dismissed Ed Miliband's launch of One Nation Labour last week. "He was signalling he was turning to the right but actually in everything he said he was turning to the left – a tax on wealth creation, a tax on business, a tax on success. You can't preach One Nation and practise class war," he said.

Today he will declare: "My mission since the day I became leader was to show the Conservative Party is for everyone: North or South, black or white, straight or gay. But above all – to show that Conservative methods are not just the way we grow a strong economy, but the way we build a big society. That Conservative methods are not just good for the strong and the successful but the best way to help the poor, and the weak and the vulnerable."

His claim will anger critics who argue that the most vulnerable are the victims of the cuts and an economic strategy that is failing.

In a move to placate the euro-sceptics of his party Mr Cameron gave his strongest hint yet that he will offer the British public a referendum on the UK's relationship with the European Union.

Yesterday Mr Cameron said a separate referendum would be the "cleanest, neatest and simplest way" to give people a say on Europe.