Scotland's most senior prosecutor has slammed the BBC for broadcasting "inaccuracies and innuendo" over the Crown Office's handling of Glasgow's bin lorry crash.

Lord Advocate Frank Mulholland said claims made in what he called a "sensationalist documentary" on the tragedy shown earlier this month were "simply not true".

The Crown Office has come under intense criticism from the families of the six who died when refuse truck driver Harry Clarke ran them over in and around George Square last Christmas after losing consciousness at the wheel.

Grieving relatives told the BBC documentary, called Lies, Laws and the Bin Lorry Tragedy, that they felt they had been misled by Crown Office officials.

They said the Crown had taken a decision not to prosecute Mr Clarke before learning that he had suffered a previous fainting episode while driving a bus that he had not declared to the DVLA.

They also used the documentary to claim that one very senior Crown official had referred to Mr Clark as a "fat, uneducated West of Scotland" man.

The Crown has denied the claims previously but Mr Mulholland and Crown Agent Catherine Dyer have now issued a lengthy defence of their officials on the Crown Office's staff website.

In the document, Mr Mulholland reveals that he took the highly unusual step of personally ringing the controller of BBC Scotland to ask that the allegations not be reported.

The statement, entitled "Lord Advocate and Crown Agent express support for staff", said all circumstances of Mr Clarke's driving record were known before the decision not to prosecute him was made.

The statement, which was leaked, said: "It was for these reasons that the Lord Advocate took the unprecedented step of telephoning the controller of BBC Scotland to seek to persuade him not to broadcast these defamatory statements."

The statement added that the BBC had refused a briefing offered and had been contacted by Crown communications staff asking for corrections.

Mr Mulholland and Ms Dyer said they had complete support for the senior Crown official who was accused of insulting Mr Clarke.

The BBC chose to name the civil servant, who, because of his job, cannot reply.

The statement said: "There were many aspects of the programme with which we take issue including the completely inaccurate assertion that the Crown took not to take criminal proceedings against the driver in ignorance of there being evidence suggesting that the driver had an episode of impaired consciousness at the wheel of a bus in 2010.

"That is not the case.

"However, what really concerned us was the assertion [an official] referred to the driver as a fat, uneducated, west of Scotland man at a meeting with bereaved families in March 2015. This is simply not true.

"The allegation that such words were used was made only when the BBC were making the documentary nearly nine months after the meeting.

"When we were advised, a week or so ago, that the BBC intended on broadcasting such an allegation we were very concerned for a number of reasons.

"Firstly it was not true, secondly a colleague confirmed it was not true, thirdly such an allegation was wholly inconsistent with [the official's] unblemished record of well over 30 years as a dedicated public servant and also that as a civil servant he should not be identified and subject to personal attack attack regarding the carrying out of his official duties."

A Crown Office spokesman said: "The Crown Office has repeatedly explained in public that we had all the relevant evidence before the decision was taken not to prosecute the driver of the bin lorry.

"We were concerned by the factual inaccuracies contained in a recent documentary and the lack of balance it provided and took steps to inform staff of the factual position.

"The Crown has consistently made it clear that the comments attributed to an official in the documentary were disputed."

A spokesman for the BBC said: “We stand by our programme which examined claims of systemic and human failures that were raised by relatives of victims of the tragedy.” He had no further comment.

Crown sources declined to add anything to the statement.