A FRESH probe has been launched into the behaviour of former minister Mark McDonald after a colleague made a number of explosive allegations.

Parliamentary authorities have referred allegations of sexual misconduct to the Commissioner for Ethical Standards in Public Life in Scotland.

It comes after SNP MSP James Dornan claimed one of his staff members suffered a campaign of harassment at Mr McDonald’s hands, leaving her unable to work and contributing to her hospitalisation.

Holyrood’s standards committee said passing the case to the Commissioner was “the most appropriate” way of dealing with the unprecedented claims.

Convener Clare Haughey MSP added: “The Commissioner is resourced to carry out this type of investigatory work, although we appreciate the sensitivities associated with this unique area.

“We do not think it would be appropriate for the committee to undertake its own investigation and there is no procedure or precedent for the committee to do so.

“We understand that due process must be followed and this will take time regardless of who carries out the investigation. It is in no one’s interest that this process becomes drawn out. We are confident the Commissioner will recognise this.”

The Commissioner’s probe is expected to be substantially more detailed than any information currently in the public domain.

If Mr McDonald was found to have broken the rules, he could be sanctioned and even suspended from parliament.

Mr McDonald returned to Holyrood earlier this week for the first time in four months after resigning as SNP childcare minister over sexual misconduct claims.

An internal SNP report into his behaviour said he had persistently pestered two women with inappropriate messages, and had exploited his position of power.

Mr McDonald quit the SNP earlier this month but has resisted calls to step down as an MSP.

Ms Haughey said a “more robust process” was required to allow claims of misconduct against MSPs to be investigated.

But she insisted any new process would have to balance openness and transparency with privacy and a duty of care.