London (CNN) — Two top leaders at the BBC resigned on Sunday amid an escalating scandal over impartiality and bias that plunged Britain’s public broadcaster into one of its biggest crises in recent years.

The BBC’s most senior executive, director general Tim Davie, and the chief executive of the news division, Deborah Turness, both quit after the leak of a deeply critical memo that, among other things, revealed that the BBC had misleadingly edited a speech by US President Donald Trump to make it appear that he had directly called for violence on January 6, 2021.

In a note to staff on Sunday afternoon, Davie said his resignation was “entirely my decision.” He added that as director general, he took “ultimate responsibility” for mistakes made by the BBC.

Turness said the controversy over a documentary made by the BBC’s “Panorama” series had “reached a stage where it is causing damage to the BBC – an institution that I love.”

The resignations come after the Telegraph newspaper published details of a leaked internal BBC dossier compiled by Michael Prescott, who had been hired to advise the BBC on editorial standards and guidelines.

In an internal whistleblowing memo, Prescott revealed that last year the BBC had broadcast a “doctored” Trump speech, making it seem that the president had encouraged Capitol Hill rioters, telling them he was going to walk with them to “fight like hell.”

In fact, Trump said in his speech in Washington, DC, on January 6, 2021, that “We’re going to walk down to the Capitol, and we’re going to cheer on our brave senators and congressmen and women.”

Trump welcomed the news of the resignations and thanked the Telegraph for “exposing” corruption, which he called a “terrible thing for democracy.”

“These are very dishonest people who tried to step on the scales of a presidential election,” he wrote on his Truth Social platform.

The allegations led White House press secretary Karoline Leavitt to blast the BBC as “100% fake news” and a “propaganda machine.”