By politics.co.uk staff
David Cameron will face his biggest event on the world stage as he attends the G8's latest summit in Canada.
The prime minister will be discussing banking reform, international crime and security and overseas aid with other world leaders.
He will also hold one-on-one talks with Barack Obama, after the US president's decision to sack outspoken General Stanley McChrystal yesterday.
That move followed the Afghanistan commander's criticisms of White House staff up to and including Mr Obama. It was discussed with Mr Cameron in a phone call earlier this week.
David Petraeus, who commanded coalition forces in Iraq during the troop surge, was appointed to take over in Afghanistan.
Meanwhile Mr Cameron's biggest test is dealing with the ongoing environmental crisis in the Gulf of Mexico, caused by energy firm BP.
Mr Cameron has been keen to point out that the company is Anglo-American in terms of both shareholders and employees. He told the Commons yesterday he hoped to see a "strong and stable" BP.
But Mr Obama faces huge pressure to move against the firm as popular anger against BP continues to rise.
The G8 is made up of Britain, the US, Russia, France, Germany, Canada, Japan and Italy.