In sunny Glasgow, many voters said they wanted Britain to stay in the European Union Thursday but were well aware that an overall Brexit result could lead to Scottish independence.
"Being in the EU is an advantage for Scotland. It would be silly to leave," said Gemma Rosaria, a 24-year-old office worker, arriving to vote in the EU referendum in the Broomhouse area of east Glasgow, Scotland's biggest city.
"I don't want a Brexit but if there's a Brexit that could be an advantage for Scotland because we can have a new referendum," said Rosaria, adding that she had voted for independence in 2014.
Scotland's independence bid, led by the Scottish National Party (SNP), was thwarted in that vote, which unionists won by 55 percent to 45 percent.
The pro-EU SNP, which dominates Scottish politics, still wants independence but says it will only call for another referendum if a clear majority of Scots back it after a Brexit vote.
"If we were to leave the EU, I'd prefer to break from the UK," said Michael Renfrew, an economics student with a ginger beard and beach shoes.
"The decision-making and the power would become far too centralised in London," the 23-year-old said.
Amanda Walker, a 42-year-old teacher, added: "Better stay with what we got." Pointing to her ginger-haired daughter, who was in a school uniform, she added: "This vote is important for her".
In the car park outside, David Turner, a local SNP councillor, was trying to win over any undecided voters.
"In Scotland, there will be a large 'Remain' vote," the 49-year-old said, as he handed out leaflets.
Polls have shown Scots are far more favourable to the EU than fellow Britons, who are heavily divided.
Scottish First Minister Nicola Sturgeon has said Scotland's expected massive vote for staying in the EU could hold the balance on a national level.
"I think it's really important to keep Scotland and the UK in the EU because there's lots of jobs and trade and investment that depends on our place in the single market," Sturgeon said, casting her vote.
"The polls see this on a knife edge across the UK which makes it really important to go out and vote today if you want to make sure that our place in the European Union is protected and we don't allow Tory divisions to drag us out of Europe," she added.
The campaign has pitched Prime Minister David Cameron, who led the "Remain" camp, against fellow Conservatives on the "Leave" side, including popular ex-London mayor Boris Johnson.
Several people were concerned that Britain leaving the EU would strengthen the centralisation of power in London.
Vincent Mellon, an assistant physiotherapist speaking in central Glasgow, said England and Scotland were "supposed to be equal parties".
"If only England voted out, that would not be fair," he said, adding: "People that are leading the 'Out' campaign have no interest in Scotland".
But Alex Blackshire did not want to hear talk about another independence referendum.
"There's been so much division during the last campaign. I don't want it to happen again," the 25-year-old executive said.
Even in Glasgow, there were a few exceptions to the pro-EU mood.
Taxi driver James Ballantine, 44, said he would be voting to leave the European Union.
"There are too many migrants from Europe. People come here and get jobs, benefits," he said, at the wheel of his cab.
"We need to take back control of our country."