ONE of the most long-awaited public inquiries to be held in Scotland is due to get under way tomorrow.

The statutory inquiry into historical abuse of children in care will be headed by leading QC Susan O’Brien and is expected to last four years before reporting back to Cabinet Secretary for Education Angela Constance.

It will investigate the abuse of children in formal institutional care including by religious orders, as well as council-run children’s homes and secure care.

It will also extend to those in foster care, long-term hospital care and boarding schools.

The inquiry, announced in December, will have the power to compel witnesses to attend and give evidence, and Constance previously pledged that where crimes are uncovered the “full force of the law’’ would be used to bring those responsible to justice.

It comes after 15 years of relentless campaigning by victims of child abuse in orphanages stretching back decades and follows a pledge by the SNP in opposition that they would hold one when they took power.

Last night a representative from one victims’ group said there was a sense of relief among survivors that the inquiry was finally getting under way, but also disappointment that it excluded certain aspects victims had wanted, including reparations for abuse they had suffered.

“Emotions are mixed,” said Alan Draper, parliamentary liaison officer for In Care Abuse Survivors.

“There was a sense of euphoria when the inquiry was announced in December, but it has taken nine months to get started and people are feeling weary.

“There is also a sense of anti-climax of remit,” added Draper.

The inquiry suffered a setback in June when two religious orders launched a legal challenge over O’Brien’s appointment.

The action by the Congregation of the Poor Sisters of Nazareth and the Daughters of Charity of St Vincent De Paul against Scottish ministers was later dismissed.

O’Brien is best known for heading an investigation into the death of toddler Caleb Ness who was killed by his father in 2001.

Her report found failings at almost every level in the handling of the infant’s case before his death, prompting a major overhaul of social-work services in Edinburgh.

Responding to her appointment in June, O’Brien said: “I appreciate that no-one can provide full justice for any victim of abuse in childhood, but the Scottish Government is anxious to enable victims to tell us what happened to them and the impact it had on their lives.

“The inquiry panel will try to identify any lessons from past failures which will help to keep our children safe in the future.”

Details of the inquiry’s hearings are to be made public and a website is also due to be launched.

Previously public inquiries have been held into the Dunblane massacre, the cost of the Scottish Parliament building and the deaths of patients at the Vale of Leven Hospital in Alexandria following the C difficile outbreak in 2007-08.

Earlier this year the Scottish Government promised that the inquiry would be “an opportunity to shine a light, where none has been before, on an appalling failure of many of Scotland’s children”.

But Constance also came under increasing pressure to get the promised inquiry off the ground after the deaths of several former care residents, including a well-known campaigner Elizabeth McWilliams, and the ageing profile of the group.