HOLYROOD'S by-election bandwagon will be rolling into Dunfermline this weekend.

The vote to elect a successor to the disgraced former MSP Bill Walker takes place on October 24 and there is much at stake for all the parties. Now that the referendum year-to-go milestone has passed, they can focus their energies on the scrap in Fife.

And a scrap it will be. The circumstances of the poll guarantee it. Walker was yesterday jailed for 12 months after he was found guilty of 23 assaults on three ex-wives and a step-daughter over 30 years. Though he was swiftly expelled from the SNP when the allegations were revealed by the Sunday Herald, the question of how he came to be selected as the Nationalists' candidate in 2011, despite warnings about his behaviour, is one the party will not be able to escape over the next four weeks. If the bookies are to be believed, it is an issue it will not be able to overcome: Labour starts as clear favourite to take the seat. So far it has not missed an opportunity to demand an apology from the SNP for "forcing Bill Walker on us," as candidate Cara Hilton put it minutes after the Nationalists' picked their hopeful, Shirley-Anne Somerville. The LibDems and the Tories are unlikely to be any less reticent, making Dunfermline an extremely difficult by-election for the SNP.

That puts a lot of pressure on Labour. It has not held Dunfermline since 2007, when Scott Barrie lost the predecessor Dunfermline West seat to LibDem Jim Tolson, yet it looks like it is Labour's to lose. In the SNP landslide two years ago Walker pipped Labour's Alex Rowley by just 590 votes so a tiny swing of less than 1% is all that is required to make Ms Hilton, 38, a local councillor, the town's next MSP. In addition to reminding voters about Walker's selection, her campaign will also try to make an issue of Ms Somerville's current job - director of communities with the pro-independence campaign Yes Scotland - and her old job as a regional Lothians MSP, when she backed the SNP Government's decision to scrap the Edinburgh Airport Rail Link, a project that would have improved routes for Fife's commuters.

For its part, the SNP is also preparing to go on the attack. One of the big local issues is the council's plans to close three schools. As a member of the Labour-led council, Ms Hilton will get the blame. The experienced and able Ms Somerville will also stand as a defender of the Scottish Government's package of universal entitlements, such as free prescriptions and bus passes for the over-60s, which has been questioned by Labour. "I will vote to protect the people's policies," she has said. Schools and the social wage, then. It worked for the Nationalists in the recent Aberdeen Donside by-election and will make for a strong campaign in Fife, even with the millstone of Bill Walker hanging round their necks. It would be foolish to predict an easy victory for Labour.

A victory of some sort, though, is vitally important for Johann Lamont's party. The flurry of opinion polls published this week showed a strong lead for the pro-UK side in the referendum battle, but also highlighted the SNP's enduring popularity as a party of government. A Scottish Progressive Opinion survey stood out for the simple fact it gave Labour a lead over the SNP in the race for Holyrood votes, the first poll do so for ages. But normal service was resumed with Ipsos Mori's poll for STV which again showed Alex Salmond's party out in front, with 41% saying they will vote SNP at the next Holyrood election and 37% backing Labour. What is more, the First Minister's approval rating, plus-8, remained higher than Johann Lamont's at plus-6. After six years in government that is a remarkable achievement and shows Scotland is not rushing to put its faith in Labour once more.

The next Holyrood election is not until 2016. Scottish Labour is a long way from constructing the detailed policy platform that will define Ms Lamont's leadership and by which the public will ultimately judge it. But signs of progress are essential. In Aberdeen Donside Labour slashed the SNP's majority but never seriously threatened victory, finishing 2000 votes in arrears in the end - respectable progress but not spectacular. Anything less than a solid victory on October 24 would come as a serious blow to Labour hopes of defeating the SNP and regaining power in 2016.