Cameron tells Tory activists that he refuses to 'play it safe'

David Cameron yesterday claimed he was happy to "take the hit" over the Government's controversial NHS shake-up and refused to "play it safe" over reforms to welfare, education and planning.

As Downing Street was recovering from the shock departure of his strategy director, Steve Hilton, the Prime Minister challenged his Lib Dem coalition partners and opponents by declaring that he would push through "bold" policies to ensure an outright Tory victory in 2015.

In what was billed as a landmark speech to "redefine" his premiership with three years to go to the election, and in a nod to Mr Hilton's radicalism, Mr Cameron told Tory activists: "I didn't come into politics to play it safe."

The PM gave his strongest signal yet that he is preparing to sack the Health Secretary, Andrew Lansley, in an autumn reshuffle for failing to carry the medical profession with the Government over NHS reform. While the Education Secretary, Michael Gove, was singled out for praise for "showing how radical action can lead to rapid change", Mr Lansley's name was absent.

No 10 announced on Friday that Mr Hilton would be taking a year's academic sabbatical in the US from this summer, appearing to confirm rumours that he is unhappy at the pace of change within the coalition.

Mr Cameron failed to mention the environment in his speech to the one-day Tory spring forum yesterday, fuelling speculation that the departure of Mr Hilton, a leading proponent of green policies, will be the final nail in the coffin of the PM's claim to lead the "greenest government ever".

Mr Cameron, under fire for being marginalised in Europe and for taking three days to admit he had ridden the horse the Metropolitan Police had lent to Rebekah Brooks, attempted to calm fears in his party that he has lost momentum. He even joked that he had "ridden" with London's Mayor Boris Johnson to the conference – but that it had been on the Tube.

In a veiled jibe at the Lib Dems, who are attempting to put their party stamp on the Budget later this month, Mr Cameron said he refused to take the "easy path". "When the decisions are tough, the temptation gets greater. And when you're in coalition, the temptation is greater still. Fortune favours brave governments, and that's what we must be."

Mr Cameron said the Welfare Bill, which finally passed last week, was the "toughest, boldest action of the lot". The PM argued that without the controversial shake-up to the NHS – which rebel Lib Dems will attempt to kill at their spring conference this week – "sooner or later the cracks would have started to show: queues would have grown, patients would have been let down. So frankly I don't care about taking a hit. I care that it works to avert that crisis, to make the NHS strong enough for the future."

Yet Mr Cameron faces a fresh Commons rebellion over Europe within weeks, as Tory Eurosceptics prepare to use an upcoming vote on the EU's bailout mechanism to defy the PM.

The Independent on Sunday has learnt that Labour's leader, Ed Miliband, is being urged to help the Tory rebellion by using Europe as a "wedge issue" to expose divisions in the Government. One option considered by party strategists is for Labour MPs to abstain in the Commons vote on ratifying a treaty on the European Stability Mechanism (ESM).

The move would follow a similar act by the French Socialist presidential candidate, François Hollande, whose party abstained on the treaty vote in the French parliament.

Mr Miliband met Mr Hollande in London last week. While not voting down the treaty outright, the abstention allowed the centre-left party to force a debate about growth and jobs, said Labour sources, because as it stands, the ESM is a "significant austerity-driven process".

"How do we best expose divisions in the Government?" said a Labour source. "Europe is Cameron's big weakness. It is a wedge issue."