Ed Miliband’s relationship with Len McCluskey was defined in a brief camera shot at the Labour party conference in 2010. After praising trade unions, Miliband added that he would have no patience with ‘waves of irresponsible strikes’. Several rows back, McCluskey, who three days earlier had helped Ed defeat his brother David in the leadership election, was filmed shaking his head and shouting ‘Rubbish!’ Given that McCluskey’s Unite union pays most of Labour’s bills, his word was seen as a veto.