(Bloomberg) -- When European Union President Donald Tusk referred to the “special place in hell” for Britain’s Brexit campaigners, it reflected a growing fear and frustration in Brussels that Prime Minister Theresa May is hostage to hardliners in her party.

A longer-than-scheduled, bad tempered phone call between May and Tusk a week ago prompted a surge of concern in EU circles that May is unable to get any divorce deal through Parliament, according to European officials who declined to be named. Tusk was horrified that May was still asking the EU for solutions to end the impasse rather than coming up with credible ones of her own. Seven days later, the despair hasn’t subsided.

May visits Brussels on Thursday as part of her efforts to get the EU to change the most controversial part of the divorce deal -- the Irish border backstop. Officials said they are braced for a tense set of talks between her, Tusk and European Commission President Jean-Claude Juncker that are unlikely to bear much fruit.

It’s a view shared on the British side too: A person familiar with the situation in London said on Wednesday the government isn’t expecting May to bring a revised Brexit deal back to Parliament by Feb. 13, a self-imposed deadline.

May will visit Brussels for the first time since EU leaders refused to improve the Brexit deal at a summit in December. The deal was then rejected in Parliament in January by a historic margin. Parliament then mandated May on Jan. 29 to go back to Brussels to renegotiate the backstop. If no deal has got through Parliament by March 29 then May will face the choice of letting the country crash out into legal limbo or extending membership in a humiliating U-turn.

The contents of last week’s 45-minute phone call between May and Tusk -- the day after the Jan. 29 vote -- soon filtered down to EU governments. In their eyes, including those that are Britain’s natural allies, May now has little credibility left, two officials said, asking to remain anonymous because of the sensitivity of the situation. Since last week’s votes in the House of Commons, there’s a growing belief that she will be unable to win support from pro-Brexit campaigners in her party.

Tusk is now hoping May will come to Brussels with “a realistic suggestion on how to end the impasse," he said on Wednesday.

That’s when he took aim at the Brexit campaigners. With Irish Prime Minister Leo Varadkar standing beside him, he wondered “what the special place in hell looks like for those who promoted Brexit without even a sketch of a plan how to carry it out safely.”

--With assistance from Robert Hutton and Alex Morales.

To contact the reporter on this story: Ian Wishart in Brussels at iwishart@bloomberg.net

To contact the editors responsible for this story: Ben Sills at bsills@bloomberg.net, Emma Ross-Thomas, Robert Hutton

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