(Bloomberg Opinion) -- Trick question: Who is in control of Brexit? Theresa May or parliament?

Over two nights of voting, British lawmakers crossed their arms and said “no” to various proposals. No to the prime minister’s divorce agreement, they said on Tuesday. No to leaving the European Union without a deal, they said on Wednesday – twice.

On Thursday, they voted no some more: No to delaying Brexit in order to hold a second referendum. No to delaying the exit date and holding more votes to find out what MPs really want. “The no’s have it,” Speaker John Bercow barked over and over.

Finally, though, the “ayes” got one: After several big government defeats this week, May’s own motion seeking to delay Brexit passed.

But even victories in Brexit-land look suspiciously like government defeats. May’s proposal only won out because a rival amendment that would have allowed parliament to wrest control of Brexit from Downing Street had been defeated by the narrowest of margins. Even May's own Brexit secretary voted against it.

May’s de facto deputy, David Lidington, warned lawmakers that Hilary Benn’s proposal to allow parliament a series of indicative votes on the various Brexit options next week would usurp the role of the executive and have “far-reaching and long-term implications for the way in which the U.K. is governed and the balance of powers and responsibilities in our democratic institutions.” But Lidington also conceded that the government itself would offer MPs some votes on other options; that seemed to work.

Cross off March 29; Brexit will now almost certainly be delayed for at least three months. The choice still before MPs is very much as Olly Robbins, May’s top Brexit negotiator, was overheard describing it in a Brussels bar last month: a decision between May’s Brexit deal, now twice rejected but by no means dead, and a long extension.

Securing that delay will require the unanimous agreement of the EU; a European Commission spokesperson was quick to note that an extension is not automatic. While unity has been a key feature on the Brussels side in the negotiations so far, this decision rests with member states, not the European Commission; they may very well express different views.

EU members would almost certainly require the U.K. to set out clearly how the extension would be used; they might make financial demands and would require the U.K. to participate in the elections to the European Parliament in May – something neither Britain nor many EU countries are keen to see happen.

Those conditions might help May to win more support for her deal, which she will likely put before parliament again next week ahead of the European Council summit, and possibly a fourth time in the unlikely event she manages to win any further assurances from EU leaders directly. She has always counted on Brexiters to see her deal as the only way to ensure the U.K. really leaves the EU; there are signs that more of them are falling into line.

A second referendum looks increasingly like a long-shot – more than half of the House voted down an amendment calling for one. Partly this was tactical. The main lobby group pushing for it said it was too early to put the vote before the House, and the Labour Party didn’t support the proposal either – even though its party policy is to support a second plebiscite. Still, the result suggests little support in parliament exists for that option.

After Thursday’s vote, May left the chamber, but Labour leader Jeremy Corbyn stood up and repeated his call for cross-party agreement around the idea of staying in the EU’s customs union permanently. This isn’t a moon-shot. Back in July, the government only succeeded in defeating a Labour motion calling for the U.K. to do just that by a handful of votes. But doing so would be regarded by Brexiters as a betrayal, bring the Conservative Party’s division to the fore, and probably spell the end of this government.

Theresa May remains, but her role has undeniably been altered this week. She has always viewed herself as a public servant, but she has now become the servant prime minister. She can propose, but others decide; her influence, even within her own party and government, is minimal. In a country where the majority party not only dictates the agenda but normally gets its way, this is a highly unusual constitutional arrangement.

Eventually parliament will need to do more than just say no. But what happens next is not in May’s hands or even parliament’s. So who really is in charge? Right now, it’s for the EU to decide. This road to taking back control takes you through some strange places.

To contact the author of this story: Therese Raphael at traphael4@bloomberg.net

To contact the editor responsible for this story: Edward Evans at eevans3@bloomberg.net

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Therese Raphael writes editorials on European politics and economics for Bloomberg Opinion. She was editorial page editor of the Wall Street Journal Europe.

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