In the centre of Lerwick, two offices square up across a busy street.

In the orange corner, the Liberal Democrats have been able to keep close tabs on their SNP rivals during a by-election campaign that has surprised many by becoming a tighter race than expected.

On Thursday, voters in Shetland will go to the polls to select their next MSP after the resignation of Tavish Scott, the former leader of the Scottish Liberal Democrats.

He has represented this area at Holyrood since the Scottish Parliament first opened 20 years ago and his decision to stand down has set up an intriguing contest.

As safe seats go, on paper at least this is Scotland's number one - at the last general election Scott polled more than two thirds of the vote, 44% ahead of the SNP.

The isles have been a stronghold for the party since Jo Grimond's victory here in 1950 - but the SNP sniff the chance of a shock win.

They have thrown everything at this campaign, with First Minster Nicola Sturgeon visiting three times, and several members of her cabinet also making the trip north.

Victory would show their party in ascendancy after 12 years in power, and create the impression that if they can win here, they can win anywhere.

It would also deal a blow to Jo Swinson early in her leadership of the UK party.

"It's a massive mountain to climb, but we're giving it our best shot," one SNP activist told STV News.

Another claimed momentum was on their side, but whether it has swung far enough in time is another matter.

The Liberal Democrats, meanwhile, are confident they can hold on.

"At this late stage those who were maybe thinking about switching are swinging back in our favour," according to one party member who has been knocking on doors.

In all, there are ten candidates standing, including UKIP and the Scottish Greens, who are fielding their first ever hopeful in a Highlands and Islands constituency race.

There are also four independents who could end up playing a significant role.

One is tipped to take a significant number of votes from the Liberal Democrats, which in a tight race may prove decisive.

The election has been fought around local issues, predominantly the cost and funding of the ferry services.

But Scottish independence and Brexit have inevitably also featured.

Shetland voted heavily in favour of Remain in 2016, although there is a large fishing community growing impatient at the lack of progress over the issue.

The Conservatives say they are the only ones that can deliver on the result of the EU referendum.

Meanwhile, Labour wants to improve broadband services and reduce centralisation.

Whoever wins this race has 18 months to deliver on their promises made during his campaign.

Then voters will have the chance to deliver their verdict again at the Holyrood election in 2021.