Theresa May has been urged to distance her Government from “Trump style” anti-democratic attacks on the BBC after the public broadcaster was accused of bias in its Brexit coverage by dozens of MPs.

Just over 70 MPs – predominately from the Conservative benches – wrote to Lord Hall, the organisation’s director general, criticising its inability to break out of “pre referendum pessimism” and “accept new facts”.

Licence fee payers, they added, “have the right to expect better”.

But Labour’s deputy leader Tom Watson has urged the Prime Minister and Karen Bradley, the Culture Secretary, to distance themselves from the assault on the BBC’s coverage of Britain’s exit from the European Union.

In a statement Mr Watson said: “The BBC is one of the world’s finest news broadcasters and we should all value its impartiality, integrity and balance coverage. It is the BBCs job to report the facts, not be a cheerleader for any cause of party”.

He added that all politicians “dislike” the way some stories are covered, “but we should never seek to interfere with the independence of the BBC by publicly accusing it of bias and making implicit threats about its future”.

“Theresa May and Karen Bradley must make clear their commitment to the independence of the BBC and distance themselves from attacks on it by politicians who have an agenda the BBC does not and should not share”.

The Liberal Democrat MP Tom Brake added the letter was a “Trump style attack” on the BBC and is “an appallingly anti-democratic move by the hard Brexit camp”.

He continued: “The BBC does not exist to be exist to be a cheerleader of the Government, and instead of attacking free speech these MPs should be holding Theresa May to account over her headlong rush into a hard, destructive Brexit.

“Press freedom is vital to our democracy, and pointless attacks like this further expose a worrying, authoritarian streak in May’s Tory party”.

Signatories of the letter sent to Lord Hall included the former Cabinet ministers Iain Duncan Smith and Theresa Villers, alongside dozens of their colleagues, DUP MP’s and three Labour MPs – Kate Hoey, Kelvin Hopkins and Graham Stringer.

Responding to the allegations of bias, the BBC said in a statement that it was their role to “scrutinise and analyse the issues on behalf of the public and to hold politicians to account across the political spectrum”.

They added: “That is what the BBC has been doing. It is what the BBC will continue to do. It is precisely because of this that the public trusts the BBC.”

The letter, which was put together by the Conservative MP Julian Knight, who campaigned to stay in the EU, added that the BBC had suffered a “collective nervous breakdown” over the referendum result.

The letter adds: “It particularly pains us to see how so much of the economic good news we’ve had since June has been skewed by BBC coverage which seems unable to break out of pre-referendum pessimism and accept new facts.

“Some of the signatories of this letter shared many of the concerns about the economic impact of Brexit, but all are delighted to find forecasts of immediate economic harm were at best misplaced. So-called ‘despite Brexit’ reporting may be expected of a partisan press, but licence fee-payers have the right to expect better.”