A court bid to bring a rare private prosecution against Glasgow bin lorry crash driver Harry Clarke has been rejected by senior judges.

The Dumbarton family of three crash victims took their case for the 59-year-old to be put on trial to the Appeal Court in Edinburgh earlier this year.

The unusual legal move followed a controversial Crown Office decision not to prosecute Mr Clarke, who had blacked out behind the wheel on the day of the fatal crash almost two years ago, on December 22, 2014.

Judges Lady Dorrian, Lord Menzies and Lord Drummond Young had been considering the Bill for Criminal Letters since hearing final arguments in the case in October and ruled on Friday the family cannot pursue a private prosecution of Mr Clarke, our sister paper the Evening Times has reported.

The court also rejected a similar plea for a private prosecution of motorist William Payne, lodged by the families of students Mhairi Convy and Laura Stewart, who were knocked down and killed in Glasgow in 2010.

Mr Clarke was driving the bin lorry when it went out of control in Queen Street on December 22 2014, killing six people in total.

Relatives of crash victims Jack and Lorraine Sweeney, aged 68 and 69, and their granddaughter Erin McQuade, 18, brought the private prosecution attempt to court.

Stephenie Tait, 29, Jacqueline Morton, 51, and Gillian Ewing, 52, also died in the collision.

A fatal accident inquiry (FAI) last year heard Mr Clarke lost consciousness at the wheel and he had a history of health issues - including a previous blackout in 2010 when at the wheel of a stationary bus - but had not disclosed his medical background to his employers or the DVLA.

The Crown Office insisted there was insufficient evidence in law to raise criminal proceedings against Mr Clarke but the families of the victims disagreed.

In the separate case, Ms Convy, 18, and Ms Stewart, 20, were walking in Glasgow's North Hanover Street on December 17 2010 when a Range Rover apparently lost control, mounted the kerb and hit them.

An FAI found the crash happened after Mr Payne suffered a ''vasovagal episode'' and temporarily lost consciousness.

He was initially accused of causing the deaths of the students but the charges against him were dropped in November 2013.

The three judges heard detailed arguments in September and October from the families and from the Crown, who did not support either private prosecution bid.

In a brief hearing, judge Lady Dorrian told the court the Bills would be refused in either case.

There was audible sobbing from a member of the public gallery as the decision was given.

During the earlier hearings, which could not be reported at the time, Lord Advocate James Wolffe QC argued there was "not sufficient evidence to support prosecution" in either case.

It is important that prosecutors can take decisions independently - and must be free to take unpopular decisions, he argued.

John Scott QC, representing Mr Clarke, said the prosecution bid wanted to rely on the sheriff's FAI conclusions but that the determination of the sheriff was not admissible in evidence.

The solicitor advocate also said other parties have started considering private proceedings in other cases and to grant this one could "open the floodgates".

Gordon Jackson QC, for Mr Payne, said the Crown had made the correct decision on the evidence.

He argued the whole purpose of FAIs could be undermined by the threat of private prosecutions, with no-one wanting to give evidence over fears they could later face charges.

The sheriff who oversaw the bin lorry FAI ruled the accident might have been prevented if Mr Clarke had "told the truth" about his history of blackouts.

Sheriff John Beckett QC found Mr Clarke "repeatedly lied in order to gain and retain jobs and licences", and "deliberately concealed relevant information from the DVLA".