Mr Macintosh said on Saturday that the party machine has turned on his supporters to prevent a leadership contest between himself and deputy leader Kezia Dugdale, who announced on Friday she planned to campaign for the job after Jim Murphy announced he would resign next month.
Sources suggested that Miss Dugdale’s supporters were trying to pressure others to withdraw support from Mr Macintosh, while one unnamed MSP was reported to have described the situation as being like “rats in a sack”.
And Mr Macintosh said his backers had been “put under incredible pressure to withdraw their support. They are being bullied and intimidated . . . so we don’t have a contest”.
Mr McLeish said the accusations sounded serious and called on Mc Macintosh to provide more details.
“I think people have lost trust in us and we need to work hard to fight it back,” he said. “But I think what struck me was, and I don’t know whether the allegations that Ken Macintosh is saying are true or false, when you use words like bullied and intimidated and pressurised these are serious concerns. I think Ken has to spell it out in a bit more detail.
“My main concern is for the Labour Party, this is not the way we should be conducting business, but to be fair to Ken Macintosh, if there are serious issues that have to be dealt with, then clearly the party in Scotland, has to have a look at what’s going on.”
Mr McLeish went on: “If this is a party of fraternity and fairness and goodwill and transparency, let’s actually practice that, get to the bottom of Ken Macintosh’s comments, get Jim Murphy’s report and then we can move forward.”
Ms Dugdale, who was elected to Holyrood four years ago, said she was “proud” to have won the support of 20 of Scottish Labour’s 38 MSPs in the first 24 hours after announcing her intention to stand.
And she revealed one of her first moves would be to look at scrapping the protection of sitting list MSPs to bring through fresh talent.
“I support opening up the list system because I want to see new people come forward to stand for Labour. People from all corners of Scotland, all walks of life. There are SNP MPs sitting on the benches of the House of Commons who haven’t been a member fo their party for a year. If it’s good enough for them it’s good enough for us. Ultimately, the good thing about opening up the list system is that party members decide who goes to the top of the list.”