The Shadow Chancellor urged MSPs to get behind the Scottish Labour leader, and hit back at Ian Murray's comments labeling Leonard a 'nodding dog'.

“Richard's election was a huge breakthrough for the progressive politics Scotland desperately needs." McDonnell told the Herald.

“What people need to do, both in terms of MSPs, the shadow cabinet and the party overall, is get behind the man who will lead Labour to victory.”

McDonnell also compared the briefing operation against Leonard to that of 'Chicken Coup' against Jeremy Corbyn in 2016.

“The most important lesson we have learned from Jeremy’s leadership is, yes, there might be some people who might not be completely supportive, but if they can get onside and the party can unite, we can be in a situation, as we were in the last general election, where we outperformed all expectations.”

Leonard's allies have pointed to a series of leaks from the Shadow Cabinet as a main factor for the reshuffle of Labour's frontbench in Scotland.

“It’s exactly as Jeremy went through in that first period. I don’t think it’s as bad as that, but I think it is very much like it.” said McDonnell.

“In all elections, there’s always some elements that have the potential for grudges because they have not won, because they haven't succeeded, and they have found it difficult to come to terms with the new political climate.”