ACTOR Peter Mullan has criticised the BBC for "horrendous bias" in its reporting of the Scottish independence referendum.

Mullan, 55, who was brought up in Peterhead and Glasgow, said the coverage "broke his heart" and claimed the BBC was used as a political weapon throughout the 2014 campaign.

The BBC was regularly accused of pro-union bias in the lead up to the referendum, prompting thousands to protest outside its Glasgow headquarters just days before the vote.

Some campaigners also called for political editor Nick Robinson to be sacked following a public altercation with Alex Salmond.

Mullan, who has appeared in Trainspotting and the Harry Potter films, said he is a "massive supporter of public broadcasting and the licence fee".

"I will be to the day I die," he said. "I believe in the BBC, on principle, because most of the education I got when I was a kid I got through watching the BBC.

"I, Claudius introduced me to the history of the Roman empire. BBC reruns of David Lean films introduced me to Dickens.

"Panorama made me want to go to libraries and find out about the world. I mean it when I say I owe everything to the BBC.

"So to see the horrendous bias that went on against the Yes campaign before the referendum - to see the BBC used as a political cudgel against a legitimate democratic movement - really broke my heart."

The biggest protest against the BBC came on September 14 last year when thousands gathered in Glasgow's George Square before marching towards the BBC Scotland headquarters at Pacific Quay.

A line of police had to stand on the front steps of the building but the demonstration passed off peacefully with "no issues", according to Police Scotland.

At the time the BBC defended its coverage, describing it as "fair and impartial".

A petition calling for the dismissal of Nick Robinson also attracted more than 16,000 signatures after a news report by him claimed Alex Salmond had failed to answer a question on major businesses expressing reservations over a Yes vote.

When the then First Minister was asked if the broadcaster's reporting was biased, he replied: "Yes, absolutely. Of course it is...but they don't realise they're biased. it's the unconscious bias, which is the most extraordinary thing of all."

An academic is media research also accused both the BBC and STV of bias in their referendum coverage - a claim they both refuted.

Mr Mullan's comments came as he also criticised the BBC over their lack of working class dramas.

The actor, who stars in BBC Scotland's new dramatisation of the Iain BAnks novel Stonemouth, said the broadcaster is "terrified of class".

"You can have working-class comedies, but drama? No, even if it's the criminal class, they get better suits and live in nicer houses," he said.

Donalda MacKinnon, head of programmes and services at BBC Scotland, said she disagreed with Mr Mullan's assessment of the referendum coverage.

She added: "We would be very happy to extend an invitation to him to visit our newsroom anytime so that he can see for himself a highly skilled and professional operation.

"Holding all political leaders to account - no matter which party they represent - is one of the cornerstones of impartial journalism. It is what our audiences, rightly, expect and what we will continue to uphold."