David Cameron has said his party has "a huge mountain to climb" in order to win the next general election.

Cameron was speaking ahead of he first anniversary of his election as Conservative leader.

The Tory chief said his party had made significant progress in that time, but sill needed to climb higher in he polls if it is to secure a Commons majority.

However he expressed confidence that this could be achieved.

"I think we can do it. I'm not one of those politicians who sort of stands up rallying and says, 'we will win', I say we can win, we can do this," Cameron told ITV1's Sunday Edition programme.

"Of course it's a big mountain to climb, but Labour's majority was made in one election, it's much smaller than it was, it can be unmade.

"We can do it, we've got a huge mountain to climb."

Cameron insisted that he would stick to his centre ground strategy and not be deflected by the calls of some right-wing commentators to change course.

"I was determined, on being leader of the Conservative Party, to get our party back into the centre ground, to get us into the mainstream of debate in Britain," he said.

"I ran for election of the Conservative Party on that ticket and I've done that ever since.

"Yes, I get attacked by newspapers who'd like me to just bring out all the old policies, but I haven't wavered one inch from the strategy that I said was the right thing for our party and also the right thing for our country, because you've got to do the right thing in politics, you can't be blown off course by one commentator or another having a bit of a pop at you - that's part of life."