A misleading edit in a BBC documentary has become the target of a $1 billion lawsuit threat from US President Donald Trump and triggered the resignation of the British public broadcaster’s director-general,

The BBC's boss and its head of news quit following criticism over bias at the British broadcaster, including the way it edited a Trump speech.

Deborah Turness and BBC director-general Tim Davie both stepped down in recent days as a result of a growing scandal over coverage of President Donald Trump.

In a letter sent to BBC Chair Samir Shah and general counsel Sarah Jones on Sunday, Trump attorney Alejandro Brito threatened a lawsuit over a BBC Panorama documentary that allegedly included "false, defamatory, disparaging, and inflammatory statements" about the president, and demanded it be retracted immediately, Fox News reported.