FAMILIES of the Glasgow bin lorry tragedy victims have grounds to challenge the decision of the Crown Office not to prosecute the driver, one of Scotland's highest-profile solicitors has claimed.

Leading civil lawyer Cameron Fyfe said a judicial review had a greater chance of success than the private prosecution being sought by one of the affected families.

Unlike a private prosecution, Mr Fyfe said legal aid was available for a judicial review, which would require proving the decision by the Crown not to prosecute Harry Clarke was unreasonable, irrational or an error.

He also called on Scotland's parliamentarians to change the law to make it less difficult to secure a private prosecution.

The Crown Office said two months after the December 2014 incident that no charges would be brought against Mr Clarke or his employers, Glasgow City Council.

Lawyers for the family of one of the six victims of tragedy, Jacqueline Morton, have applied to the High Court for permission to bring a private prosecution against Mr Clarke.

If it went ahead, anything Mr Clarke said in the FAI could be used against him in a subsequent trial.

Last week Mr Clarke declined to answer many questions for fear of incriminating himself.

Mr Fyfe said public prosecutions were rare as it requires the Crown to grant consent for something it had already refused, while the second hurdle, a Bill of Letters from the High Court, was only cleared in exceptional circumstances.

He said that without a form of legal aid the costs for a private prosecution "would be hopelessly expensive".

But he added: "There is however another avenue they may wish to consider. It is possible to obtain legal aid to raise an action for a judicial review in the Court of Session.

"Under this procedure, they could challenge the decision of the Crown Office not to proceed with the prosecution. "They would have to prove however, either that the decision was unreasonable and irrational or that the Crown Office had made a mistake in the law in reaching their decision."

He said that in 2002 he had acted for a client who had been sexually abused by a monk at his Catholic school. Although the Crown had decided not to prosecute due to the monk's age was too old, Mr Fyfe had obtained an opinion from a QC that the prospects of success were good, with Legal Aid granted.

He added: "Perhaps it is time for the Scottish Parliament to change the law to make a private prosecution less difficult. It would be more equitable if there was no need to obtain the consent of the Crown. It could also be suggested that Legal Aid is automatically granted if a sifting Judge considers that a private prosecution should proceed."

The inquiry has already heard that Mr Clarke was unconscious at the wheel of the Glasgow City Council bin lorry when it veered out of control on Queen Street.

It has also heard that he suffered an earlier blackout at the wheel of a stationary bus in 2010 when he worked for First Bus as a driver.

This episode, and his history of dizziness and other ailments, were not disclosed to Glasgow City Council and the Driver and Vehicle Licensing Agency (DVLA).

The inquiry has heard that he may have lied to the DVLA about a previous blackout in 2010, while documentary evidence showed he also failed to declare a previous collapse at the wheel of a bus three times while applying for posts at Glasgow City Council.

Closing submissions are due to be heard today at the inquiry. Mr Clarke declined to answer many answers when he took the witness stand last week.