PRESSURE is mounting for judges to hold more pre-trial hearings on complex medical and forensic evidence after a mother convicted of murdering her toddler son was cleared on appeal.

Kimberley Hainey, 38, was this week cleared of all of her convictions connected with the death of her child Declan. The boy was nearly two and had not been seen alive for eight months when he was found mummified in his cot in 2010.

The heroin addict was cleared after appeal judge Lord Clarke suggested key witnesses who gave evidence against her – including eminent forensic anthropologist Sue Black – were not experts in the relevant field.

Lord Clarke called for more pre-trial hearings so that judges could rule on the admissibility of such evidence. "Putting matters colloquially, it cannot be right for a trial judge to allow an obvious 'quack' doctor to speak to a subject in a supposed expert way in relation to which he has no qualifications."

The judge added: "It is to be noted that in England and Wales, the rules of procedure require that where there is to be medical evidence led and relied upon it should be considered at a pre-trial hearing.

"It may be that the time has come for some thought to be given to providing for such an approach in Scotland."

Lord Clarke last night won the support of one of Scotland's most senior forensic scientists, Professor Allan Jamieson.

The defence specialist, head of the Scottish Forensic Institute, said: "Pre-trial hearings are valuable. They help to focus the important issues and they identify what is agreed and what is not agreed and the court can be focused on the point of disagreement."

There are pre-trial hearings before all Scottish trials at which parties can object to evidence proposed by another. However, Lord Clarke is suggesting such evidence should be tested ahead of trial, whether there is an objection or not.

Mr Jamieson has been lobbying for unfettered access to prosecution forensic evidence before trials.

A Scottish Government spokeswoman said judicial practice was a matter for the judiciary. "The judiciary already has powers to consider medical evidence at preliminary hearings in advance of High Court trials."