Just a few months ago, the idea of a so-called “people’s vote,” or second referendum, on Britain’s withdrawal from the European Union was regarded by most commentators as fanciful. Now, an increasing number see it as the way out of Britain’s Brexit nightmare.

Admittedly, Prime Minister Theresa May is adamantly opposed to the idea, and she insisted once again on Monday that there would be no second plebiscite, saying that it would “break faith with the British people.”

But her options are closing in, and she has changed her mind abruptly before, most recently by postponing the parliamentary vote on her beleaguered Brexit plan, which she says will now take place the week of Jan. 14.

[What is Brexit? A simple guide to why it matters and what happens next.]

On Monday, Jeremy Corbyn, leader of the opposition Labour Party, called for a vote of no confidence in Mrs. May, though he did not press for a motion that might bring down her government. Nor was it clear whether the vote he wants, which is designed to embarrass Mrs. May, would be held anytime soon.