Culture Secretary Lisa Nandy said the BBC must fight to restore trust after criticism that a Panorama documentary misled viewers by editing a speech by Donald Trump.

She said a review of the broadcaster's charter would ensure a "genuinely accountable" BBC, defending it as a "national institution".

BBC director general Tim Davie earlier told staff "we've got to fight for our journalism" after the US president's threat to sue the corporation for $1bn (£760m).

A leaked internal BBC memo said the Panorama film misled viewers by splicing together parts of Trump's speech on 6 January 2021 and made it appear as if he had explicitly encouraged the Capitol Hill riot. BBC chair Samir Shah has apologised.

Davie resigned on Sunday alongside BBC News CEO Deborah Turness after mounting pressure over that memo, which was written by Michael Prescott, a former independent external adviser to the broadcaster's editorial standards committee.

The memo also accuses the BBC of issues within its Gaza coverage, particularly by BBC Arabic, anti-Trump and anti-Israel bias and one-sided transgender reporting - among other "troubling matters".

Davie told staff on Tuesday: "We have made some mistakes that have cost us, but we need to fight", adding that "this narrative will not just be given by our enemies, it's our narrative".

He said the BBC went through "difficult times… but it just does good work, and that speaks louder than any newspaper, any weaponisation".

Later on Tuesday, speaking in the Commons, Nandy warned MPs attacking the broadcaster to "consider just what is at stake".

She told the Commons: "There is a fundamental difference between raising serious concerns over editorial failings and members of this House launching a sustained attack on the institution itself, because the BBC is not just a broadcaster, it is a national institution that belongs to us all."

She added that the BBC "has faced criticism from all sides for its coverage of highly contentious and contested issues, and [has been] accused of giving too much airtime to particular parties, and for giving them too little".

The BBC's charter expires at the end of 2027 and the once-a-decade process of reviewing it is set to begin shortly, which she said would help it "renew its mission for the modern age".

Nandy said there was a concern over how long the BBC took to respond to criticisms which undermined trust.

She acknowledged "serious concerns and failings" on the part of the BBC Arabic Service, but urged strong support for the World Service, which she said was "a light on the hill for people in places of darkness".

BBC figures on the corporation's editorial guidelines and standards committee will face questions at a hearing in the coming weeks.

Shah and board members Sir Robbie Gibb and Caroline Thomson are expected to attend a session called by the Commons culture, media and sport committee.

Former editorial standards advisers Michael Prescott, the author of the leaked memo, and Caroline Daniel will also be invited to give evidence.

Shadow culture secretary Nigel Huddleston said there are "too many examples of bias" at the BBC and said the corporation required "institutional change".

In a post on social media on Tuesday, Conservative leader Kemi Badenoch said that while the BBC as an institution "ought to be treasured", it has "continually let down licence fee payers".

Trump threatened to take legal action if the BBC did not make a "full and fair retraction" of the Panorama programme by Friday. The corporation has said it will reply in due course.

In the staff call on Tuesday neither Davie nor the BBC chair mentioned Trump's legal threat.

Downing Street has said this was a "matter for the BBC".

"It is clearly not for the government to comment on any ongoing legal matters," the prime minister's official spokesperson said.

"Our position is clear, the BBC is independent and it's for the corporation to respond to questions about their editorial decisions."

Asked whether there were concerns the issue would affect Sir Keir Starmer's contacts with Trump, the spokesperson said the two had a "very strong" relationship.

The spokesperson would not be drawn on whether the BBC should apologise directly to the president.