A FIRM of private detectives has been hired by the SNP to investigate a new complaint made against former childcare and early years minister, Mark McDonald.

The MSP has not voted or spoken in the Scottish Parliament since resigning from his Cabinet position in November after he admitted that “some of his behaviour” had “been considered inappropriate”.

It later emerged this related to text messages he had sent to a woman.

Two weeks later he was suspended by the party after “new information” arose about his conduct, also relating to text messages.

It was reported yesterday that now a further complaint has been made by a woman about his behaviour.

According to a Sunday newspaper the firm of private detectives is due to submit its report to the SNP over the coming days. Party bosses will then decide what action, if any, to take against McDonald.

It is understood McDonald has told party bosses he vehemently denies any wrongdoing over the new complaint.

Meanwhile, following his three month absence from Holyrood, opposition politicians have called for him to return to the Scottish Parliament or quit his Aberdeen Donside seat.

Labour MSP Rhoda Grant said: “The Mark McDonald situation is getting ridiculous. He disappeared in a cloak of secrecy and has been missing for three months now.

“Serious questions need to be asked about how the SNP handled this situation. It cannot be right that the people of Aberdeen Donside have an AWOL MSP.”

Lib Dem MSP Alex Cole-Hamilton said: “Mark McDonald has let down his constituents in the north east, who have been without an MSP for months. He owes his constituents an explanation.”

A by election would be called should McDonald stand down, a development which could see Alex Salmond run as a candidate. It was reported in December that friends of the former First Minister have said he would be keen to stand should McDonald resign his seat.

The Aberdeen Donside seat held by McDonald contains part of the Gordon Westminster seat Salmond lost in last year’s snap general election.

A SNP spokesman said: “An independent investigation remains ongoing.”

McDonald was first elected to Holyrood as a list MSP for the North East in 2011, but following the death of Brian Adam in April 2013, he was selected as the SNP candidate for Aberdeen Donside and resigned his North East seat to fight the by-election.

He held the seat for the SNP and was returned to the Scottish Parliament in June 2013. He then held the seat in the 2016 Holyrood election winning 56 per cent of the vote and increasing the SNP majority to 11,630 - the largest majority in the whole of Scotland.

Following Nicola Sturgeon’s reshuffle on 18 May 2016, McDonald was appointed minister for childcare and early years.

In this role he was responsible for the launch of the high profile baby box policy. He was replaced by Maree Todd as childcare and early years minister.