By Christeen Winford BBC Radio Scotland's Investigation

Kathleen Marshall said changes were needed

Kathleen Marshall has told BBC Radio Scotland's Investigation programme that a better way has to be found to balance our fundamental legal principles with looking after children who are victims of sexual abuse.

On Monday's programme, some of these vulnerable child witnesses tell how they feel damaged by the very legal system they thought would protect them.

They tell of protracted delays, unexplained cancellations and repeated questioning by strangers which forced them to constantly relive their original trauma, coupled with an almost complete lack of practical and emotional support.

They said this left many of them so confused and helpless that they were been driven to drink, drugs and self-harm - some to the point of suicide.

'It haunts me'

Craig describes cutting himself "because it was the only way to cope, to deal with it. And an easier way than taking it out on other people".

Another youngster recalls "being torn to shreds" by a procurator fiscal testing whether she could stand up in court.

"I just collapsed under it and I think that was one of the worst things and still to this day it haunts me," she said.

These reports come as no surprise to Ann Houston, chief executive of Children 1st.

It's time for urgent change, to remove barriers to young people speaking up, giving good quality evidence and allowing real justice to be done Ann Houston Children 1st

She also chairs a group of professionals called Justice for Children which is campaigning to improve the experience for young people appearing as witnesses in court.

She said: "Some youngsters describe the legal process as more damaging than the original abuse.

"We know from children who phone Childline that many of them will not seek the protection they need, precisely because they are fearful of the process."

The Crown insists that improvements like the 2004 Vulnerable Witnesses Act has markedly improved the legal process for young people.

However, supporters of Justice for Children disagree.

Some witnessed said they felt damaged by the system

Ms Houston said: "It's time for urgent change, to remove barriers to young people speaking up, giving good quality evidence and allowing real justice to be done.

"Only this can prevent thousands of unsupported youngsters developing long-term emotional problems and a myriad of paedophiles walking free."

The solution, according to Simon di Rollo QC, is an accelerated legal process for crimes involving children, with specially-trained judges, lawyers and QCs.

But the children's commissioner says we need to go further and re-examine some of the most cherished principles of Scottish justice, like corroboration and the rights of the accused.

"We have to have a very principled discussion about them, making sure that we include the rights of children, so that we get to a system that actually delivers justice for them as well as everyone else," said Ms Marshall.