Why is there a by-election in Rutherglen and Hamilton West?

Margaret Ferrier, who was elected to represent the South Lanarkshire seat in 2019, was ousted by her constituents in Scotland’s first recall petition.

The petition was signed by 11,896 constituents, well above the 8,113 needed to reach the threshold of 10%.

The Herald: Margaret Ferrier with Nicola Sturgeon ahead of December 2019 general election

The recall petition was opened after Ferrier was suspended from the Commons for 30 days over her multiple pandemic rule breaches and subsequent criminal conviction.

She was ordered to carry out 270 hours of community service after pleading guilty to wilfully exposing people “to the risk of infection, illness and death”.

The former SNP politician had a majority of 5,230 at the last general election when she took the seat back from Labour who had taken it off her in 2017.

Who’s going to win?

Labour’s Michael Shanks is by far the favourite to win the seat. Normally what happens in by-elections parties are circumspect, but very early on Labour has been uncharacteristically confident.

Back in May, before the vote had even been called Jackie Baillie admitted that failing to win would be a disaster for the party. She told reporters that defeat here would lead to some serious “soul searching."

Labour needs a swing of just 5%.

Even the SNP has been managing expectations in recent days. Humza Yousaf says he’s hopeful that Katy Loudon will win, but that the party is “very aware” of the “difficult context” surrounding the contest.

Coral has Labour odds-on at 1-16 to by-election, the SNP is on 8-1.

Everyone else is on at least 100-1.

The Herald: Scottish Labour candidate Michael Shanks with party deputy leader Jacqui Baillie

When will we get a result?

It depends on how many people vote. Historically, turnout at by-elections is low, with an average of 50.2%. However, with this seat being a key marginal for over a decade, there’s a reasonably high number of postal votes, around 15,060, slightly more than 20% of the total electorate.

While that should speed things up, there are real fears from the parties that new legal requirements for voters to bring photographic ID could put people off or lead to them being turned away from the polling station.

That said, we’re expecting a result between 12.30 am and 1am. Of course, The Herald will be at the count at South Lanarkshire council’s HQ in Hamilton and will bring you the result as soon as we get it.

What does the result mean?

For Labour, this is all part of their journey to government. Last week, Sir Keir Starmer said victory would be a "milestone" on the party's "hard road back to power".

If they win here then it shows the party is on course to take seats off the SNP at the next general election, making it much easier for them to win a majority when the country goes to the polls, widely expected next year.

A defeat would see party HQ pretty much give up trying too hard in Scotland and instead focus on the red wall.

If the SNP managed to pull off a surprise win here, it will be a huge boost to Humza Yousaf. It will show his party can hold on to their vote despite the arrests, the finances, the camper van, the splits and everything else.

But with defeat expected, a loss here shouldn't have too many ramifications for the First Minister.

Unless it’s a really, really big defeat.

Then some of those criticisms about the weakness of his leadership from the fringes of the party could go mainstream.

The Herald: Humza Yousaf

What happens next?

There’ll be a big party for the winners. If Labour triumphs, we can expect Sir Keir Starmer in the constituency at some point on Friday morning. And if the SNP pulls off an unexpected victory, then we can expect Humza Yousaf in South Lanarkshire for a rally.

Labour conference starts over the weekend, and Michael Shanks will be the man of the weekend. The SNP’s conference kicks off next weekend.

In terms of what actually happens, the winning candidate will need to wait until October 16 when Parliament returns from recess before they can be sworn in and take their seat on the benches.