BERWICK-UPON-TWEED, England — This is England’s northernmost town, and it has changed hands between the Scots and the English more than a dozen times in the last 1,400 years. It hasn’t been a true border outpost since the unification of the two countries more than 300 years ago, but it may soon become one again.

And the people of Berwick, many of them of Scottish origin, are not too happy about it, fearing that the uncertainty and instability could disrupt a feeble economic recovery. The opinion polls are close, the debate is exhausting and the mood is anxious.

“People feel and fear that however it goes, the relationship between Scotland and England will never be the same,” said Tom Forrester, a town councilor.

“My heart tells me that most right-minded people will see that it is safer and better for us to stay in this relationship with each other,” said Liz Murray, who owns a shop that sells cookware in Berwick but lives across the border in Scotland. “But I’ve seen enough of the passion of the Scots to see that that might carry the day.”