The separatist movement is led by Mitch Sylvestre, a gun shop owner from the town of Bonnyville, and Jeffrey Rath, a lawyer based in Calgary. They are both members of a group called the Alberta Prosperity Project, which argues that the province’s economic growth has been hindered by years of Liberal party rule in Ottawa.

Successive Liberal governments of the last 10 years have put environmental policies above helping Alberta develop its oil and gas sector, they argue. They say Alberta would get to keep more of its wealth if it splits from Canada.

Chris Scott, founder of pro-separatist group Let’s Talk Alberta, told BBC News on the eve of the poll that the campaign had already achieved some of its goals, regardless of what happened on Monday. “The key is the conversation has started and it needs to continue,” he said. “What’s started can’t be stopped now,” he added.

Those who oppose separation say a newly independent Alberta would be left responsible for billions of dollars in debt. They warn that the uncertainty – which they liken to the UK’s Brexit vote to leave the European Union in 2016 – would drive thousands of jobs and investment out of the province.

Carney has called on voters to deliver a decisive vote against separation. Speaking at a rally on Thursday, he warned that the stakes were high.

“The world has become more dangerous and divided. Some outside our borders are working to break us so they can own us,” Carney said, echoing warnings he has made in the past about his country’s ongoing trade war with the United States.

Alongside the separation question, Albertans will vote on nine other issues – a number of which focus on whether the province should have more control over its immigration system.

Hundreds of thousands of people had voted early by post ahead of Monday, and early figures suggested a strong voter turnout.

The province’s election officials will count the ballots by hand, and have 48 hours to complete the task – starting from no earlier than 20:00 local time on Monday (02:00 GMT on Tuesday).

The key question, on separation, will be counted in its entirety first. Officials have said results should be available in the early hours of Tuesday.