May's election debacle has revived feuding over Europe among Conservatives that her predecessor David Cameron hoped to end by calling the referendum and leaves EU leaders unclear on her plan for a "global Britain" which most of them regard as pure folly.
While "Brexiteers" have strongly backed May's proposed clean break with the single market and customs union, finance minister Philip Hammond and others have this month echoed calls by businesses for less of a "hard Brexit" and retaining closer customs ties.
With discontent in europhile Scotland and troubled Northern Ireland, which faces a new EU border across the divided island, Brexit poses new threats to the integrity of the United Kingdom.
It will test the ingenuity of thousands of public servants racing against the clock to untangle 44 years of EU membership before Britain is out, 649 days from now, on March 30, 2019. For the officials sitting down on Monday, at least on the EU side, a major worry is Britain crashing out into a limbo, with no deal.
For that reason, Brussels wants as a priority to guarantee rights for 3 million EU citizens in Britain and be paid tens of billions of euros it says London will owe on its departure.
With a further million British expatriates in the EU, May too wants a deal on citizens' rights, though the two sides are some way apart. Agreeing to pay a "Brexit bill" may be more inflammatory.
Brussels is also resisting British demands for immediate talks on a future free trade arrangement. The EU insists that should wait until an outline agreement on divorce terms, ideally by the end of this year. In any case, EU officials say, London no longer seems sure of what trade arrangements it will ask for.
But Union leaders, including German Chancellor Angela Merkel and French President Emmanuel Macron, are also determined not to make concessions to Britain that might encourage others to follow.
When 52 percent of British voters opted for Brexit, some feared for the survival of a Union battered by the euro crisis and divided in its response to chaotic immigration. The election of the fervently europhile Macron, and his party's sweep of the French parliament on Sunday, has revived optimism in Brussels.
