So what does the pollster think the winner needs to do?
Diffley spells out three priorities: become relevant, develop a relationship with the prime minister (who he says is currently popular in Scotland) and spell out appealing policies.
Some aspects of that will be easier than others.
One senior party insider agreed with much of Mark Diffley’s analysis, warning “it’s not an easy inbox”.
They told me there’s a need to change approach, and Labour might look to learn from a rival party – the Scottish Greens.
The Green strategy has been to get their policies taken on by the SNP. You’ll often hear the Greens talk about Scottish government decisions and essentially say: ‘that was our idea’.
And Labour, this insider argues, should be taking the same approach.
There could be offers to back SNP budgets in return for more public control of buses or higher wages for care workers, for example.
At future elections, Labour could then have tangible “wins” to point at.
It would be a change in approach from a party that tended to oppose or abstain on budgets in the last parliament.
