British MPs have urged Barack Obama and Mitt Romney to dial down the rhetoric on Iran in the third and final presidential debate set to take place on Monday evening.
Both men have said "all options" remain on the table to prevent the Iranian regime getting hold of nuclear weapons although Romney has tried to paint Obama's sanctions policy against Iran as a failure, endangering the safety of Israel.
Sir Ming Campbell, the former leader of the Libera Democrats and foreign policy spokesman, told The Huffington Post UK he was worried about the more bellicose language of Romney.
"My anxiety about Mr Romney is his lack of experience and the generalisations that he has pronounced in relation to Iran and the Middle East," he said.
"Obama is by nature cautious, we know that, we've seen that. My concern is Romney may have given the impression of a much more adventurous policy in the Middle East and that appears to be based on unqualified endorsement of the position and actions of Israel, whereas Obama has been much more fastidious in his approach and not sought to create so called 'red lines' which might trigger automatic actions."
He added: "The problem with pledges made in the course of elections is people expect you to adhere to them when you're elected. The right in the US would expect to him to honour the much more robust foreign policy statements."
But the former Lib Dem leader said that the cautious approach to foreign policy was not always appropriate, particularly in Afghanistan where British troops fight alongside American forces.
"It took him [Obama] a long time to decide whether he was going to embark upon the surge in Afghanistan, I think from time-to-time thoughtfulness on part of president has looked like indecision," he said.
"Only White House insiders could tell you where Obama's reluctance in some respects has been due to genuine considerations or simply an over cautious approach."
Labour MP John Spellar, who serves as a shadow foreign affairs minister, said he hoped the debate focused on the need for "constructive" peace talks in the Middle East.
"Romney is just into point-scoring and political tactics whereas I think Obama is actually trying to to get a resolution and I would like that to come out," he said.
"I think Obama can put his case forcefully, he can stress his support for a two-state solution and that both parties should be coming to the table urgently."
Spellar also said he hoped the debate audience would hear about the "considerable body of military and security opinion" in Israel that was against a strike on Iran's nuclear facilities and not ramp up the rhetoric about conflict.
Prime minister David Cameron has, in tandem with the White House, said "nothing is off the table" when it came to dealing with Tehran and that the world should not have to live with a nuclear armed Iran.
However in a speech to a gathering of the Jewish community at an event in London last week, Cameron said the "relentless sanctions" put in place were having an impact no-one expected a year ago. “They have slowed the nuclear programme," he said.
“I have said to [Israeli] prime minister Netanyahu that now is not the time for Israel to resort to military action.
"I also refuse to give in to those who say that the current policy is fatally flawed, and that we have no choice but military action, " Cameron said.