“Kate Forbes should hang her head in shame, she betrayed the promises made to the family by the Scottish government.

“This isn’t the end, because as we said to the chief constable today, charges must follow for those police officers who have been shown to have lied, to have broken the law, to have engaged in criminality.

“Once the public inquiry ends, we expect the solicitor general to do her job.

“What exactly is the solicitor general waiting for?”

A Crown Office and Procurator Fiscal Service spokesperson said: “We welcome every opportunity to reflect upon our work and identify any possible areas for improvement.”

Police Scotland deputy Chief Constable Alan Speirs said: “Police Scotland has participated fully in every aspect of the public inquiry and our commitment to positively assist the chair in discharging the terms of reference remains unchanged.”