Anas Sarwar has ruled out making a fresh bid for the Scottish Labour leadership, as he said the party needs to “urgently take a look at itself”.
In an open letter to Labour members in Glasgow, he urged leaders Jeremy Corbyn and Richard Leonard to tackle infighting and do more than “speak for a clique or faction” within the party.
His plea came at the end of a disastrous week for Scottish Labour, with the party polling just 9% in the European election.
In addition, MSPs Neil Findlay and Daniel Johnson quit the party’s Holyrood front-bench team.
Mr Sarwar, who lost out to Mr Leonard in a leadership contest after Kezia Dugdale quit, insisted: “The Scottish Labour Party needs to urgently take a look at itself and change if we are to ever compete, never mind be the party of Scotland again.”
But when asked on Twitter if he would be mounting a leadership challenge, the Glasgow MSP responded: “Categorically no!
“This is too important to get lost in some kind of pretend personality battle. This is about the survival of our party.”
The European election, which saw the party lose the two MEPs it had north of the border, was the “worst result” in Scottish Labour’s history, Mr Sarwar said.
Following the electoral trouncing, Mr Leonard said he “hoped” Scottish Labour would back a second Brexit referendum in all circumstances, and that he would campaign for the UK to stay part of the European Union.
Members of the party’s Scottish executive committee will decide whether to adopt this as official policy when they meet on Saturday June 8.
Arguing Scottish Labour should be an “unequivocally Remain party” and an “unequivocally pro-UK party”, Mr Sarwar said the “radical” programme Labour is putting forward in other areas will only get a hearing from voters if the party is “clear on the biggest issues of our day”.
He insisted “factionalism and division” within the party “needs to stop”.
Mr Sarwar said the party needs to come together, arguing: “We can only advocate unity to the country if we demonstrate unity in our party.
“That’s why the factionalism and division needs to stop. That is a responsibility for all of us, but the culture is set at the top and leadership must come from there too.
“Rather than showing humility and reaching out, it’s deeply disappointing that those responsible for the election campaign have chosen to lash out and attack their own colleagues.”
Mr Leonard said: “The result of the European election was humbling for Labour across the UK and as Scottish Labour leader, it is my job to reflect on that and how the party moves forward together.
“That is why I quickly made it clear that we will back a confirmatory vote on Brexit and campaign to Remain.”