BBC in crisis: why did Tim Davie and Deborah Turness resign?

Director general and head of news quit amid accusations of bias over Trump and trans issues at broadcaster

• BBC director general resigns - latest updates

The BBC director general, Tim Davie, and head of news, Deborah Turness, resigned dramatically on Sunday night after accusations that the corporation was failing in its duty of impartiality. The chair of the board, Samir Shah, is expected to apologise on Monday for the way in which a speech by the US president, Donald Trump, was edited in an episode of Panorama. The show is one of a number of examples highlighted by Michael Prescott, a former external adviser to the BBC's editorial standards committee, who detailed his concerns about the broadcaster's impartiality in a memo published by the Telegraph.