BRUSSELS — Some of the smugness here is gone.

The European Union took a tough line in negotiating its divorce with Britain, wishing to preserve its unity and discourage other countries from wanting to leave the bloc. But now officials worry that what they have achieved may be “a catastrophic success.”

British politics is in meltdown after Parliament’s crushing defeat of Prime Minister Theresa May’s carefully negotiated plan for Brexit, as the process of withdrawal is known. And no other compelling alternative plan for an orderly exit is in sight, with just 10 weeks to go until Britain is set to exit the bloc.

European Union officials are now worried that Britain could leave without any agreement — a so-called “hard exit” that analysts warn could trigger a recession in Britain, causing huge backlogs, delays and shortages of goods, and badly hit the European economy, too, since more than 40 percent of Britain’s trade is with the bloc.

Yet they see no point in making any concessions now, since Mrs. May has lost control of the process.