Jim Murphy’s weekend victory in the contest to lead Scottish Labour will cause serious problems both for the party and for the left across Britain.

His party has been flagging north of the border for years and currently trails the Scottish National Party by a full 20 points in the opinion polls.

Murphy says that his leadership will mark a “fresh start” for Labour in Scotland. It had better. For all his claim that he will not lose a single Westminster seat to the SNP in May, current projections indicate otherwise.

The trouble is that Murphy is the least convincing figurehead possible for the sea-change in the party’s attitude which will be necessary if it is to reclaim the support of the working class and lead that class to electoral victory.

Indeed, the very fact of his win implies that Labour is still in denial about the causes of its decline.

A career politician, Westminster-based, who backed the Iraq war and tuition fees and maintains his support for Britain’s nuclear weapons, a former chair of Labour Friends of Israel and a Blairite who helped run David Miliband’s campaign for the party leadership at British level is a gift to the SNP’s claim to be the true voice of Scotland’s left.

That claim is nonsense. Even Murphy has been able to put clear red water between himself and the all-things-to-all-people Nationalists, matching Nicola Sturgeon’s pledge to tackle poverty and inequality but adding realism to the promise by vowing to use planned Scottish revenue-raising powers to increase the rate of income tax on the richest.

He has tried to reach out to the many Labour supporters who voted Yes in September’s referendum on independence, saying — rightly — that those on both sides who want to see a fairer, more just Scotland have more in common with each other than with many of the politicians who ran either campaign.

But he’ll find it hard to avoid the riposte: “Yes — including you.”

Murphy has never been seen as an enthusiast for devolution, and his new-found zeal for the Smith Commission must be accompanied by a clear articulation of how Labour will use Holyrood’s powers to advance social justice if he is to stand a chance against Sturgeon.

The new leader is right to remind voters that only by voting Labour can we secure the ejection of the Conservative-led coalition next year.

Morning Star readers do not need reminders of the consequences of another Tory regime.

The irreversible privatisation of the NHS, the final destruction of the welfare state and — as even privatising sell-outs like Vince Cable now admit — the end of public services as we know them would result.

But “vote for us — the other lot are even worse” is an uninspiring slogan at the best of times, and this is not the best of times.

The SNP is playing a clever game, ruling out a coalition deal with the Tories and hinting that they would be willing to prop up a minority Labour administration at Westminster.

This is a deliberate bid to reassure voters that voting Nationalist will not let the Tories in.

Since Murphy has little to recommend him to left-wing voters other than not being in the Conservative Party, it may prove lethal to Labour.

The tragedy is that if the party had an empowering vision for the reversal of austerity, the redistribution of wealth and a new deal for working people seeing their living standards fall year on year, the pundits would be debating the likely size of its majority rather than whether it can win at all.