Eight stocky men march along the imposing town ramparts, longbows and spears slung over their shoulders and heavy armour breastplates stitched onto their quilted cloth outfits.

The group, preparing for a historical re-enactment to mark the 900th anniversary of England’s most northerly town, are in character as border reivers – medieval raiders who took advantage of centuries of tension and insecurity to pillage and plunder across the lawless Anglo-Scottish borderlands.

The ramparts themselves are another reminder of how its proximity to the border has shaped Berwick: the fortifications were built in the 16th century to keep out the marauding Scots who regularly laid claim to the town.

Another Scottish advance is preoccupying Berwick this week. With just a day to go before voting in the Westminster election, opinion polls indicate the Scottish National Party (SNP) is set for a spectacular leap in its seat tally. Some surveys suggest it could even make a clean sweep of all 59 constituencies north of the border.

That would transform Scottish politics, traumatise the Labour Party and send a minor tremor through Westminster, but few communities are watching the unfolding drama more keenly that in Berwick, a town of 12,000 people just four kilometres from the border.

Worries

Kay Rose

, a retired teacher taking a stroll along the town walls, says the SNP surge has put Scottish independence back on the agenda much sooner than anyone here expected, and it worries her.

"I worked in Scotland nearly all my working life and I've got a Scottish pension, so I'm worried about the currency if they do go independent," she says. "We're apprehensive. We don't know what's going to happen."

Berwick has long occupied an ambiguous position on the map of Britain. As close to Edinburgh as it is to Newcastle, the largest city to the south, it changed hands frequently during centuries of border wars and its identity is closely bound up with its mixed influences. Its football team plays in the Scottish league and many people cross the border every day to work or study. Rose herself has family in Scotland.

She sent her daughter to a school across the border and cannot understand why Labour leader Ed Miliband insists on ruling out a coalition with the SNP. Yet she also feels the mood has changed since last September's referendum on Scottish independence. "It has aggravated the differences. I don't think it's healthy at all – I think we're better united," she says. "Nationalism is a fever, and it's spreading."

In a town keenly conscious of its place in the periphery, Rose’s anxiety is compounded by her sense that London is turning in on itself, giving up on Scotland and slowly disengaging from Europe. “If we get out of the EU and we don’t have Scotland, we’re London really, aren’t we? That’s all they’re interested in.”

Berwick has been receiving more attention than usual of late, because the retirement of the long-serving Liberal Democrat MP Alan Beith has brought the local seat into play. It's a key target for the Conservatives. Andrew Marshall, a marketing specialist who was born and raised in Berwick, has yet to decide between Labour and the Tories. Ideally he'd like an SNP candidate on the ballot paper, because he believes the party could represent local interests well and he is drawn to what he see as its more progressive policies.

“The scaremongering against them is a little bit hypocritical. The big parties have been doing deals with other parties for years,” Marshall says. “You [in Ireland] know all about it – they’ve been doing deals with the DUP. It seems to me a bit rich that when they might have a bit of power, we turn around and say, ‘we’re not having that’.”

Marshall is relaxed about the prospect of Scottish independence and believes it could even benefit his town. “Berwick became a very rich power because of the rise of Scottish nationalism and it retained that significance when the English took it over and it got a garrison,” he says. “If that border began to mean something again, I suspect Berwick would be a lot less out on a limb than it currently is. It has just been absorbed within Northumberland, which it has never been a part of.”

Frightening

Not everyone is as phlegmatic about the upheaval north of the border, however.

Derek Sharman

, a tour guide and historian who is coordinating Berwick’s anniversary celebrations, says Scottish independence was a “frightening prospect” that sent the town into “turmoil” last summer.

He believes the Scots have done very well out of the union and it galls him to think the SNP will have a large bloc of MPs “calling the shots” and making demands of a government that relies on their support. “I think they’ve had quite enough, frankly.”

Sharman was in the majority of the northeast's electorate that voted No in a 2004 referendum on whether to set up an elected regional assembly here. Instead, he would like to see a parliament for England. "The odd thing is that you can be proudly Scottish, proudly Welsh, proudly Northern Irish, but if you're proudly English someone labels you as being some nutcase racist . . . It's very sad that there isn't an English identity that can be expressed in that way."

For all that, this proud Englishman has come to a surprising and conclusion: Berwick should become part of Scotland. “I say that not because I want to be Scottish – I don’t – or because of the history, but economically speaking we’re much more linked with the Scottish border economy than we are with the northeast English one.”

Tourist destination

Berwick is beautiful, well-located and poor, he says. It should be a “mini-York”, a tourist destination, a gateway to the north. “We are 60 miles north of Newcastle and 60 miles south of Edinburgh. Would you rather be 60 miles south of your national capital or 60 miles north of the most northerly city, which itself is pretty much forgotten? So, yes, my head says Berwick should be Scottish.”