It was difficult territory as Putin, whose country supports and has armed the Syrian regime, did not hold back in his criticism of the rebels.
He said: ‘I believe you will not deny the fact that one should hardly back those who kill their enemies and eat their organs – all that is filmed. Do you want to support those people? Do you want to supply arms to these people?’
Peter Bingle, founder of public affairs agency Terrapin Communications, said the press conference was ‘a disaster’.
‘On Syria the PM is playing a dangerous game both at home and internationally. The Russian president plays politics to different rules. He knows what he wants and will tolerate no dissent. His language was deliberately brutal and direct.’
But John Slinger, a consultant for Quiller and a Labour activist, said: ‘The fact that Putin chose to use such undiplomatic language reflects badly on him, not on Cameron or on Cameron's position.’
Cameron’s position was further undermined by the rival for his party’s affections, London mayor Boris Johnson, writing in the Daily Telegraph today.
Johnson claimed it would be ‘impossible’ to arm the rebels without weapons ending up in the hands of ‘al-Qaeda-affiliated thugs’.
Johnson’s argument was attacked as ‘cynical and simplistic’ by Slinger, who added: ‘Nick Clegg's position at the weekend was classic example of limp Lid Dem foreign policy … added to Labour's wariness on the issue, Cameron could well struggle to win a vote.
‘This places the PM in a very invidious position. He is now doing what only PMs can do - engaging in secret discussions with the world's greatest power about the most important foreign policy issue since Iraq.
‘The US will be asking him what the UK can offer. Cameron will be desperate not to have his executive powers undermined like this. He'll be working on options which circumvent needing to win a Commons vote and he'll be working hard to convince Tory and Lib Dem sceptics.’
The press conference came ahead of the G8 summit in Northern Ireland, which starts today. Cameron is expected to use the UK’s presidency of the G8 to push for greater international co-ordination on corporate and individual taxation.