The Scottish Parliament on Tuesday voted in favor of seeking another referendum on independence, setting the stage for a clash between the British prime minister and the first minister of Scotland.

The motion in the semiautonomous Scottish Parliament had been widely expected to pass, with the minority Scottish National Party government and the Scottish Greens supporting it.

Advocates for Scottish independence now have parliamentary authority for a referendum. But holding a binding referendum still requires approval from the British government.

Prime Minister Theresa May has not ruled out a second referendum, but she has rejected the proposed timetable. The Scottish motion calls for a vote by spring 2019.

[Video: Scotland slams Theresa May’s Brexit speech]

Nicola Sturgeon, the first minister of Scotland and leader of the Scottish National Party, wants the referendum held within two years. In such a scenario, Britain would be engaged in negotiations to leave the European Union — a process often referred to as Brexit — while, simultaneously, Scotland would vote in a referendum on independence from Britain.

“Scotland’s future should be in Scotland’s hands,” Sturgeon said before the parliamentary vote, which was originally slated for last Wednesday but was postponed after a deadly terrorist attack in London that day.

Sturgeon met with May in Scotland on Monday to discuss the upcoming Brexit negotiations and the possibility of a second referendum on Scottish independence.

During the talks in Glasgow, Sturgeon said, May made clear that the details of Britain’s divorce deal would be known within two years.

“When that deal emerges, I think people in Scotland should have an informed choice about whether that’s the path they want to take, or whether they want to take the path of becoming an independent country,” Sturgeon told the BBC.

May has repeatedly said that “now is not the time” for another independence ballot. “Now is the time when we should be pulling together, not hanging apart,” she told reporters after her meeting with Sturgeon.

“We have a standoff, and there’s not going to be any immediate resolution,” said John Curtice, a professor of politics at the University of Strathclyde. But he said that an informal campaign for independence has begun and that the argument ahead would center on when — not if — a fresh referendum will occur.

David Mundell, the British government’s Scotland secretary, told the BBC on Tuesday, “We won’t be entering into any negotiations at all until the Brexit process is complete.”

Sturgeon has signaled that she is willing to negotiate the date “within reason.”

On Wednesday, May will trigger Article 50, the formal mechanism that will officially kick off the process of Britain’s withdrawing from the E.U. Divorce talks between Britain and the E.U. are expected to last two years.

Sturgeon dropped a bombshell this month when she said she would seek a new referendum.

In 2014, Scotland voted 55 percent in favor of staying in the United Kingdom. At the time, Scottish leaders said it was a “once in a generation” vote. But Sturgeon has argued that last year’s British referendum on the E.U. — in which a majority of Scottish voters chose to remain in the bloc and a majority of English voters opted to leave — represents a “material change in circumstances” and that Scotland risks being taken out of the E.U. against its will.

Pollsters say support for Scottish independence is roughly where it was in 2014.

Scotland is “split down the middle” on whether to have a referendum and on the outcome, said Mark Diffley, research director at the Ipsos MORI survey firm. He added that both sides hope the ongoing debate will “shift the dial.”

Later this week, Sturgeon will write to May requesting permission to hold a new referendum by spring 2019. If the request is turned down — as is expected — she said she will return to the Scottish Parliament after Easter to set out her next steps.