The British prime minister is due to have lunch on Friday with Jean-Claude Juncker in Brussels, whose executive staff, with their counterparts in Whitehall, will do the heavy lifting in negotiations that are expected to start early next year.

Despite her efforts to resolve the key conundrums of Brexit among the fellow political captains, it is below the decks in the office cubicles of the Commission’s Berlaymont building and in similar mundane engine rooms in London and other EU capitals that the legal tangles of this most complex of divorces will be unwound.

“The great leaders tend to think that they can sort things out among their colleagues,” said a senior EU diplomat who was in the room when May recently met one of her continental peers. “But it does not always happen that way in Brussels.”

Once May gives formal notice that Britain is leaving, by March she says, the Council will meet at 27, minus May, to set negotiating guidelines for the Commission. Former Polish premier Donald Tusk will be the arbiter of what deal Britain is offered, but the Council has less than a tenth of the Commission’s 33,000 staff to work on the details.

British and EU officials said that May is emulating her ill-fated predecessor David Cameron in touring European capitals and holding face-to-face meetings with fellow leaders, partly in the belief that high politics can bypass the “Brussels bureaucrats”.

“Everyone was smiling at him and saying they would help, but as soon as he left they called Brussels to say they would not go easy on him,” one EU official said. “Now it will be the same.”

“This isn’t just any old Commission negotiation,” a second senior EU diplomat said. “The heads of state and government will be following this very closely.”

By Premji