LONDON — Scotland’s first minister, Nicola Sturgeon, is launching a campaign for a second independence referendum, arguing Tuesday that Scotland would be better off economically outside the United Kingdom.

Ms. Sturgeon, who leads the Scottish National Party as well as the devolved government in Scotland, said it’s the right time to revisit the case for Scotland to leave the U.K.

“After everything that has happened — Brexit, Covid, Boris Johnson — it is time to set out a different and better vision,” she said as she released the first in a series of government papers laying out the arguments for independence.

Scotland rejected independence in a 2014 referendum, with 55 percent of voters saying they wanted to remain part of the U.K.

Ms. Sturgeon has said she wants a new vote on independence before the end of 2023. That would need a green light from the U.K.-wide government of Prime Minister Johnson, who opposes a new referendum and has said the issue was settled in the 2014 vote.

Ms. Sturgeon argues that the landscape has changed since then, most importantly because of Britain’s departure from the European Union, a move opposed by a majority of people in Scotland.

“Had we known in 2014 everything we know now about the path the U.K. would have taken, then I’ve got no doubt Scotland would have voted yes back then,” Ms. Sturgeon said in an interview with the BBC.

Ms. Sturgeon said that when she was re-elected as first minister last year, it was on a “clear commitment to give the people of Scotland the choice of becoming an independent country.”

She said Tuesday the Scottish parliament has an “indisputable democratic mandate” for the vote. Ms. Sturgeon’s party leads a pro-independence majority in the Scottish parliament, together with the Scottish Green Party.

She urged Mr. Johnson’s government to grant a special order allowing a legally binding independence referendum to be held. She is ready to discuss the terms with Mr. Johnson, she added.

Mr. Johnson’s office again rejected the bid.

“The U.K. government’s position is that now is not the time to be talking about another referendum,” Mr. Johnson’s spokesman said.

“We are confident that the people of Scotland want and expect their governments to be working together to focus on issues like the global cost-of-living challenges, like war in Europe, and the issues that matter to their families and their communities,” he added.

Like Wales and Northern Ireland, Scotland has its own parliament and devolved government and makes its own policies on public health, education, and other matters. The U.K.-wide government in London controls matters such as defense and fiscal policy.

Ms. Sturgeon unveiled the first in the Scottish government’s “Building a New Scotland” papers, which argues that neighboring, independent European countries of Scotland’s size are wealthier and fairer.

She maintained that decision-making in London is holding back Scotland’s potential, adding: “We have a prime minister with no democratic authority in Scotland and no moral authority anywhere in the U.K.”

Opposition parties have criticized Ms. Sturgeon for focusing on independence and neglecting other issues such as recovering from the coronavirus pandemic and the cost of living crisis. They say another referendum will be divisive and counterproductive to what Scotland needs.

“The distraction and disruption of another bitter referendum debate is the last thing Scotland needs right now,” a Scottish Conservative, Donald Cameron, said.