David Cameron has been "sidelined" at the G20 summit taking place in St Petersburg after MPs humiliated him by blocking his hopes of taking part in a American-led military strike against the Syrian regime, Liam Fox has said.
The former defence secretary said the failure of Cameron to be able to make good his pledge to take part in military action would give "pause for thought among our allies about the deliverability of any promises future British prime minister's might make".
Fox told the BBC's Daily Politics on Thursday that "parliament's decision last week has left the prime minister sidelined in any discussions about Syria at the G20".
He added: "The prime minister has been sent into negotiations on Syria with no hand to play and that is bad for the UK.”
The G20 meeting of world leaders was supposed to focus on the global economy, however the crisis in Syria is likely to dominate talks.
In a further blow to Cameron, it has been suggested the lack of a scheduled bilateral meeting between him and Obama is a deliberate snub by the American president in response to parliament's vote.
Iain Duncan Smith has denied the lack of a planned one-to-one meeting between Cameron and Obama was significant. However the fact the president is holding talks with French president Francois Hollande will be embarrassing for Downing Street.