For the first time since he became the frontrunner in the Labour leadership contest, Jeremy Corbyn clashed with David Cameron in the Commons this afternoon. The encounter, following the PM's statement on Syria, offered a glimpse of how the two men will handle each other if Corbyn is elected on Saturday.

After Cameron announced that the government would accept up to 20,000 Syrian refugees over five years, Corbyn challenged him to sign up to a "European-wide response to assist refugees from all parts of the world and ensure they have somewhere safe to go". He called on "Britain to play a much greater role than it does at the present time, including sorting out the misery and desperation of people living in those camps in Calais and others places - they are human beings too, who need some help and support."

Notably, he then praised the government for engaging with Iran, rather than, as most expected, denouncing the UK's targeted assassination of British Isis fighters in Syria (an act that Cameron acknowledged was unprecedented in modern times). Corbyn spoke of "The welcome remarks from the Foreign Secretary during his visit to Tehran in which he indicated that because of the new relationship with Iran there was the possibility of a wider political involvement in bringing about some degree of progress, possibly even a solution, to the desperate crisis facing Syria and of a summit featuring all the nations of that region plus, of course, Britain, the USA and Russia." His qualified praise for the government shows that he will look for consensus where possible, rather than launching perpetual attacks.

Cameron responded by stating that the UK was right not to take part in the European scheme "because we think a better for answer for Britain, which is such a major investor into these refugee camps, is to take people directly from the camps because that way we won't be encouraging more people to take this perilous journey. Where I would say Britain is absolutely fulfilling its moral responsibility is, if you take a long-term view, look at the asylum seekers we've taken, look at the people we've resettled from around the world here, we absolutely play our part."

His most significant remarks came in relation to Iran. While saying that there was "an opportunity for greater dialogue with Iran" following the nuclear deal, he added: "We ought to remember that Iran is still a supporter of terrorist organisations like Hamas and Hezbollah, which I know he describes as 'friends' but which I see very much as enemies, and also we need to make sure that Iran is playing a positive role in Syria, rather than the role it is playing now of propping up the hated Assad regime"

Cameron's scorn for Corbyn's "friends" comment (which he has defended as a diplomatic courtesy) shows that he won't shy away from attacking his likely PMQs opponent. It had been suggested by some that the Tories would go easy on Corbyn for fear of aiding his opponents in ousting him before the general election. Also of note was the unstifled laughter of George Osborne and Theresa May on the Tory side, and shadow chancellor Chris Leslie on the Labour side, as the backbencher spoke. They, like others, cannot quite believe that Corbyn - serial rebel, lifelong backbencher, unashamed Bennite - is on the brink of victory.