MARK McDonald may face a fresh probe after a public standards watchdog was urged to investigate after the former SNP MSP was found to have harassed two women by “exploiting his position of power”.

Agnes Tolmie, chair of the Scottish Women’s Convention, called upon the commissioner for ethical standards in public life to hold an inquiry to look into the former childcare minister’s behaviour.

The commissioner investigates complaints about MSPs and councillors who are alleged to have breached their Code of Conduct. The Code of Conduct for MSPs requires they treat parliamentary staff and MSPs’ staff with courtesy and respect.

It states that “complaints from staff of bullying or harassment, including any allegation of sexual harassment, or any other inappropriate behaviour on the part of members will be taken seriously and investigated".

However, the commissioner can only investigate if a complaint is made – and no complaint has been made regarding McDonald despite the findings of the SNP investigation.

Tolmie said the rules should be changed to allow the commissioner to hold an investigation without a complaint being made.

“It’s not unusual for women who are victims of alleged harassment not to make a complaint because that

immediately puts them in the spotlight,” she said. “I find it hard the commissioner can’t launch an inquiry without a complaint. The body is there to uphold standards among politicians.

“Mark McDonald has said himself his behaviour was inappropriate, so why is the commissioner not investigating?”

It is unclear whether the two women in the McDonald case worked in Holyrood, either as parliamentary staff or staff of MSPs. The SNP has declined to say, pointing out it must protect the women’s identities.

Nicola Sturgeon yesterday defended her party’s handling of the investigation into McDonald. The First Minister and SNP leader said that while any party would want to reflect on such circumstances, the process followed had been “robust”.

She made clear her view McDonald should step down as an MSP after he resigned from the SNP on Tuesday saying he would continue to represent Aberdeen Donside as an Independent MSP. The role will entitle him to collect a further £200,000 in pay before the next Holyrood election in 2021.

McDonald apologised for causing “hurt and offence” to two women when he read out a press statement in Aberdeen on Tuesday.

SNP bosses launched an investigation into reports of inappropriate behaviour by the married father-of-two, with allegations made by three women.

The findings were shown to McDonald on Monday, with investigators concluding the MSP’s inappropriate behaviour had been “deliberate in nature” and he should have known not to act in this manner.

The behaviour is said to include sending inappropriate and unwanted text and social media messages, causing distress to women through his unwanted attention and exploiting his position of power, with the investigation finding there had been “persistent behaviour over an extended period of time”.

The former childcare minister has been absent from the Scottish Parliament since the allegations against him were first made in November 2017 but plans to return next week.