Former president Jimmy Carter believes President Obama will win the 2012 election despite the woeful state of the US economy.

Referring to next year’s election, Carter said he was “optimistic” that President Obama would “fill the centre ground” mainly because the current clutch of Republican nominees had moved so far right that they would find it hard to capture “swing or even moderate Republicans”.

When questioned on Rick Perry’s use of religion within his nomination campaign, Carter, himself an evangelical who “teaches scripture every Sunday”, responded bluntly: "He's not going to win."

"I am a Christian but the separation of church and state is imperative in society," he said.

Speaking to a packed Royal Festival Hall in London, the 39th President of the United States discussed issues as diverse as Israel, North Korea, his Presidency and the role of his wife, Rosalynn, who was "born next door".

On the current crop of presidential nominees, Carter recalled how in previous elections Republican candidates moved from the centre to the right during the nomination process, then the candidate who secured the nomination spent the remainder of their campaign "moving back towards the centre".

He also made mention of the focus on immigration, saying this was a product of "a weak economy" that gives rise to "racial prejudice".

On the issue of Israel, Carter maintained his endorsement of a two-state solution, saying that Obama's overtures towards the pre-1967 border earlier this year were "genuine".

Questioned by Channel 4's Jon Snow, Carter was particularly forthright when discussing his upbringing and how that played into his personal philosophy.

"I grew up in the culture of a black community,” said the 87-year-old. As a young man he realised that legal segregation in his home state of Georgia was not only a millstone around the neck of the black community, but "also the white community that imposed segregation".

"I knew from the Bible white people weren't superior," he said.

Carter offered two reasons for what he called the "unprecedented political polarisation" currently facing the US.

Referencing the US Supreme Court's decision to allow corporations to donate as individuals, he said this has led to a culture in which the main point of a campaign was to "defame your opponent".

He also mentioned Fox News as a contributing factor in the rise of the political right, specifically in reference to the way the US has "lurched," as a questioner put it, "to a direction that no one ten years ago would recognise."

On 9/11, Carter said that the "initial US response was correct," however the country had made several "errors" since then, most notably "George W Bush's invasion of Iraq".

"It was proper for the US to go into Afghanistan," he said, but the invasion of Iraq was based on "false premises".

On Iraq, Carter said he had "personally and privately" conveyed his reservations to Tony Blair.

Although Carter said the use of drones for killing was something he "wouldn't have done," he accepted that the assassination of Osama bin Laden was "justified".