MARCO Biagi, the SNP MSP for Edinburgh Central, took to Twitter this week to take a swipe at Sarah Boyack, the Scottish Labour leadership contender.

"It's strange when you see the person you defeated in 2011 running for their party's leadership," he mused. Let's forgive Mr Biagi his snide little gloat. After all, he triumped at the last election in a seat everyone assumed was a Labour-Liberal Democrat marginal, pipping Ms Boyack by 237 votes. What was surprising was seeing a mention of Ms Boyack at all.

Nationalist politicians, commentators, bloggers and tweeters have been falling over themselves to offer helpful advice to Scottish Labour about the pitfalls of electing Jim Murphy as leader. The East Renfrewshire MP and former Scottish Secretary would be fatally undermined from the start because he serves at Westminster, they warn. Worse, he has never previously shown any interest in Holyrood. He's also a Blairite who supported the Iraq war, they note.

To be fair, these points are not made exclusively by Nationalists. Malcolm Chisholm, the veteran Labour MSP, felt it would be a catastrophe to pick an MP as leader. Ian Davidson, Labour MP for Glasgow South, accused Mr Murphy of staging a coup. But, having spoken to many Labour people this week, such voices seem to be in the minority. The vast bulk of the scorn that's been heaped on Mr Murphy has been dumped by Labour's principal opponents in Scotland, and they haven't given the other contenders, Ms Boyack and Neil Findlay, Labour's health spokesman, a second thought.

That should tell Labour parliamentarians, members and affiliated trade unions, the three groups who will choose the new leader, quite a lot. It's abundantly clear Mr Murphy is the figure the SNP would least like to see leading Labour.

Save time, Labour members serious about taking the fight to the SNP: spend 10 minutes on Twitter rather than shiver through an interminable leadership hustings in a freezing hall. That sums up the mood among a surprising number of Labour people who are not natural allies of Mr Murphy; some, indeed, who are openly resistant to his charms. Rather, it is Mr Murphy's supporters who sound most worried. "Never underestimate our capacity for making very strange choices," said one, before muttering something I couldn't quite catch about "Ed and David".

So what of Mr Murphy's chances? He's certainly the favourite but victory next month is by no means guaranteed. He should do well among MPs, MSPs and MEPs, whose votes equate to one-third of the total in the electoral college, and among the paid-up members. In the last leadership election in 2011, Mr Murphy's close ally, Ken Macintosh, topped the poll of ordinary members, suggesting Labour's rank and file are comfortable with someone towards the right of the party. However, he will need to win these two sections by a healthy margin as he's not expected to pick up nearly as much support from trade unionists.

Mr Murphy received a significant boost on Thursday when Anas Sarwar, the deputy leader, announced he was stepping down. The move paves the way for a deputy leadership contest and, depending on who stands, a more balanced team at the top of the party. Kezia Dugdale, the Lothians MSP and education spokeswoman, is raring to go. If the pair win through, their double act would mirror that of Alex Salmond, who led the SNP from Westminster between 2004 and 2007, and Nicola Sturgeon, his deputy and "Holyrood leader" during that time.

Wisely, Mr Murphy does not want to jump the gun by talking of by-elections before he is leader but it's quite possible he could be an MSP within six months, a much shorter wait than Mr Salmond. As for running a "branch office," as former leader Johann Lamont described Scottish Labour, it's safe to assume Mr Murphy will have a chat with Ed Miliband about that. Given his comments ("If I'm Scottish Labour Party leader, I'm in charge,"), it's an equally safe bet the two have come to an agreement.

No-one really knows what will happen when voting gets underway. But looking - and wincing - at polls showing Labour on course to lose scores of seats to the SNP next May, the party is well aware this could be its last chance to put matters right.