The Conservative Party are "nowhere near" regaining public trust and may not be able to win the next general election, according to their home affairs spokesman Oliver Letwin.

Speaking to the New Statesman magazine, he says: "We have a huge hill to climb. It is very large. We have to re-establish, with millions of citizens who are very disenchanted and very cross, our credibility as an alternative government."

"That isn't something we are going to be able to do in a week or a month or a year. It's something we have to try and do over four years," he added.

Letwin, who famously maintained a low profile throughout the last election after backing in an off-the-record interview proposed tax cuts that were higher than the party's policy, said Conservatives had been "too inclined to spot an opportunity for grabbing a headline and too exposed to having to reverse the decision later."

He admitted that the party must make public services, such as education, health and transport, a top priority and prove that they can be trusted to provide better quality services without spending "a colossal extra amount of taxpayers' money".

Letwin's reputation has grown with his prominent position in debates over anti-terror legislation in the Commons. And on the situation in Afghanistan he gave a strong indication that he would like to see Osama bin Laden assassinated.

"I think there are times when an enemy is so dangerous that you are entitled to kill him," he said.