Labour's failure to modernise in Scotland led to the risk of independence in a referendum, one of the party's senior MPs has told Politics.co.uk.
Ian Davidson, the Labour MP for Glasgow South West and chair of the Commons' Scottish affairs committee, has been speaking out as Scottish politicians begin to look beyond next month's referendum.
"The reasons why the SNP have done well [over recent years] has been more to do with the failures of the Labour party - the lack of modernisation of the Labour party," Davidson says.
"The SNP have been what the Labour party should have become."
His argument is that left-leaning Scottish voters who moved away from the slums of Glasgow to the new towns of Scotland dropped their political allegiance in the process.
Many of them became nationalists, he argues, on the basis that they were leaving their old identities behind. They didn't want the "Tammany Hall politics of Labour in the cities" to come with them. So the nationalists were allowed to take over from Labour as the main part of the left.
Having embraced that, and in the wake of Labour's post-Tony Blair implosion, the SNP found themselves with an unexpected majority after the last Holyrood elections.
"The only reason we're having a referendum now is because the SNP were conscious that independence is not a popular concept," Davidson argues.
"They ran for election on the basis of being more New Labour than Labour, but without the baggage of Tony Blair, the Iraq War and all the rest of it."
This was never the plan, Davidson argues. He thinks the nationalists could have made a much better go of winning the support of the Scottish people if they'd had more years in the Scottish parliament, making devolution more credible.
"People have not got sufficient trust in them to make the leap of faith because they haven't demonstrated themselves over a long enough period," he adds.
"They've been catapulted into this. On currency union, on pensions, they clearly have not thought things through, which is why the wheels are falling off the wagon."
A Labour party supporter shows just how disparate the left's interests can be north of the border
The SNP's seizure of the left in Scotland has proved decisive in a nation whose left-leaning roots go deep. They explain why Edinburgh, which if shifted down south into England would be a Tory-Liberal heartland, is oddly Labour.
They also explain the SNP's appeal. Before the advent of Margaret Thatcher, the nationalist movement had a strong conservative component, says Professor Stephen Tierney of the University of Edinburgh.
"What bound them together was a common aspiration for either devolution or independence, but it was accepted people had very different views on economics," Tierney argues, pointing out it was only in the 70s and the 80s that the SNP developed their social democratic outlook.
This posed a big challenge for Labour – and one which Davidson acknowledges his party failed to meet.
The Scottish Labour party will be hoping the fallout from the result of next month's referendum will help undermine the SNP's dominance of politics in Holyrood.
A YouGov poll for the Times released this week put support for independence up to 43% - its highest backing yet.
The four-point bump did not see a reduction in the 'no' campaign's overall lead of 14%, however, with 57% of voters saying they would reject independence on September 18th.