Nigel Farage has been seeking to find the Tory baseline on Europe, but with Cameron completely fluid on policy and willing to veer further and further right, Farage has struggled to land a destructive blow in the past couple of months.
With the NHS, especially in the wake of the Lord Ashcroft NHS poll, Farage knows Cameron cannot afford to manoeuvre to the right. Has Lord Ashcroft's latest poll revealed a vulnerable flank to the Ukip leader?
In an interview with BBC Political Editor Nick Robinson, Farage reignited the debate when asked about his original 2012 comment that he would be more confident if the NHS was funded "through the marketplace of an insurance company".
The Ukip leader's comments were devoid of any proposals, but may still be pleasing to Tory heartlands and their constituent MPs - many of whom use private insurance anyway. Despite the remarks being disowned by Ukip health spokeswoman Louise Bours MEP, Farage states he wants to see all parties "return" to the debate on NHS funding, opening a new front for Cameron on his right flank.
The latest poll from former Conservative deputy chairman Lord Ashcroft has revealed significant mistrust amongst voters about Conservative intentions on the NHS. It revealed, Labour have an 18% lead on the NHS and that shadow health secretary Andy Burnham was more trusted to tell the truth about the NHS than the Prime Minister and his Health Secretary Jeremy Hunt.
Since 2010, 51% believe the NHS has gotten worse and to add extra sting, the poll was conducted prior to the recent headlines on an NHS winter crisis.
Lord Ashcroft's poll also revealed an anxiety amongst the electorate, explaining that there is a perception that "the Tories were thought to have an ideological preference for privatisation" and even suspected that "Tories would have ties to people who stood to profit from private contracts with the NHS".
After exhausting airtime trying to neutralise his EU woes, spending much political capital at home and in Europe and after desperately moving to pacify his party on Europe, Cameron now finds himself outflanked on the NHS. The latest poll from the Guardian/ICM shows the NHS is seen as the number one issue and also shows a rising concern on the NHS (up by seven-points since a similar poll in Autumn).
NHS funding has the potential to be another controversial and internal issue for the Conservative party and voter concern for the future of the NHS could win or lose the next election. As the NHS continues to dominate the news, any controversial comments from Cameron's backbenchers could see the Tories struggling to catch up with Labour on the NHS as the general election draws closer.
Polls reflect that the Conservatives have a significant weakness on the NHS. Voter mistrust on the NHS and a seeming mismanagement of A&E this winter leave Cameron no room to move to his right.
Labour's Andy Burnham was quick to condemn the comments, "Nigel Farage has confirmed that a vote for Ukip is a vote for the privatisation of the NHS and for a full American healthcare system", adding that such a policy shows that Nigel Farage's Ukip are (helpfully for them) "more Tory than the Tories".
On the NHS, Cameron has little room to move, having shown his hand long ago and after staking his reputation on protecting the NHS. Lord Ashcroft's latest poll has revealed exactly where the Tory baseline is and reveals a great vulnerability on a top general election topic. Farage of course intends to take advantage.