It was an announcement that was supposed to provide clarity and transparency. Instead it threw the whole election campaign into chaos.

With 11 days until the United States votes to choose its next president, the letter from James Comey, the FBI director, informing Congress that more information had been found relating to Hillary Clinton’s email saga sent the country into a frenzy.

Donald Trump could barely contain his glee – describing the story which began in 2009, when Mrs Clinton was appointed secretary of state, as “worse than Watergate.”