British Prime Minister Theresa May’s meeting last Friday with President Emmanuel Macron of France is part of a wider effort to sell her Chequers plan for Brexit to European Union heads of government — and to loosen the grip of Michel Barnier, the unyielding civil servant who is conducting the negotiations on their behalf. Her campaign is failing.

Europe does not like May’s attempt at compromise and most of Britain’s voters — Leavers and Remainers alike — don’t, either. Time is running out for finding any other middle ground. Bank of England governor Mark Carney warns that the risk of a disruptive no-deal Brexit is “uncomfortably high”.

It is not too late for Britain to change its mind about this whole misbegotten venture — and Europe’s leaders, if they choose, could help.

A second referendum will be needed to reverse the Brexit decision. The costs and complexities of quitting the EU have become much clearer since the vote in 2016, and this justifies a second ballot. But the mechanics are not straightforward. If Europe’s leaders want Britain to stay in — as they should and as they say they do — they should act.

The main thing is to promise to remove any obstacles on their side to reversing Brexit. Under the process Britain has triggered, it is to leave the EU in March 2019, and it is unclear that it could now unilaterally change its mind. EU governments should say they will let Britain withdraw its notice to quit, and if necessary move the exit date back to make time for another vote. Alternatively, they could promise to let Britain rejoin the union on its existing terms during the short post-Brexit transition period that is envisaged at present.

Perhaps EU governments have come to think Britain is more trouble than it is worth, and would now prefer it to go. In that case, they ought to say so — and push for an orderly Brexit, which would serve their interests as well as Britain’s.

They could do this by offering non-voting membership of the single market, with all its rights and obligations, for as long as it takes to arrange a limited free-trade agreement of the sort that Europe has reached with other non-EU countries.

It is not in Barnier’s power to make this strategic choice. Either course would require clear direction and unanimous backing from the EU’s top political leadership. As appealing as it might be to let Britain twist in the wind, Europe should decide what it wants and press for it.