Donald Trump’s former FBI director is expected to stop short of accusing the president of obstructing justice when he gives evidence before a Senate committee on Thursday in the latest twist of a saga that has evoked comparisons with the Watergate scandal that brought down Richard Nixon.

TV networks have already begun counting down to what they are calling a “bombshell” hearing and cleared their schedules to carry live coverage of James Comey’s testimony.

He led the investigation into alleged links between the Trump campaign and the Kremlin until he was fired by the President last month.