David Cameron and US Secretary of State John Kerry secretly ganged up to persuade a nervous Barack Obama to back Britain’s bid to arm Syrian rebels, it was revealed last night. The Prime Minister and Mr Kerry’s diplomatic ambush of President Obama succeeded when they won his support for a showdown with Russia’s Vladimir Putin – a key ally of Syria’s President Assad – when Mr Cameron hosts a G8 summit in Northern Ireland tomorrow. Obama’s surprise U-turn came 24 hours after Foreign Secretary William Hague slipped into Washington almost completely unnoticed to meet Mr Kerry. In recent weeks, while...