Ian Murray MP has claimed that the Scottish Labour leadership contest is rigged to help Richard Leonard.
He made the claim that the ballot is being swung in favour of left-wing candidate Richard Leonard as a result of voting rules which allow members of Unite to cast a ballot.
To vote under Labour rules, members can either join the party as a full member, sign up as a registered supporter or become a supporter of an attached trade union.
As a result, 2,700 members of the Unite trade union have opted to sign up to vote.
Writing a letter to The Herald, the Edinburgh South MP, who has backed Anas Sarwar said the process seems “clumsy and, at worst, being rigged for a particular process.”
He stated: “There is no doubt whatsoever that the way in which Unite has signed up affiliate members to vote in the leadership election is against the rules of the Scottish Labour Party and the process,” he wrote.
“The text clearly failed to ask the recipients if they supported the aims and values of the Labour Party, nor did it ask them to consent for their data to be shared with the party.
“In order for this process to be fair and robust, the party must reconsider whether any sign-ups from this process are valid.”
Murray also questioned the actions of Alex Rowley, the interim leader, who appeared to endorse Richard Leonard at the Party conference.
A Unite spokesman said: “Ian Murray is wrong. Unite has adhered to the SLP’s rules to the letter, and indeed the general secretary and the party’s legal and governance unit have all confirmed that our affiliated members are valid.
“We urge Murray to take (Scottish Labour general secretary) Brian Roy’s advice on this and in doing so withdraw his wrongful accusations about Unite.”
A spokesperson for Scottish Labour said: “Any affiliated or registered supporter would be expected to support the aims and values of the Labour Party.
“These sign-ups are eligible and within the rules of the leadership contest.”