The speaker cited a convention from 1604 in denying May a fresh push to get her deal through.

Prime minister Theresa May was told on Monday that she cannot bring her Brexit withdrawal agreement back to the House of Commons for a third vote. House speaker John Bercow quoted a convention from parliament's rulebook, Erskine May, which stipulates that a government cannot continually bring back the same piece of legislation for multiple votes. May has already lost two meaningful votes on her deal with the European Union, first by the historic margin of 202 votes and, on Tuesday, by a mere 149. She spent Monday morning in discussions with the Democratic Unionist Party about how they might back the plan while Tory Brexiteer MPs considered their next move. The only way Bercow will allow the prime minister to return with her withdrawal agreement is if there is substantial change to it, regardless of its chances of being passed. https://twitter.com/PoliticsJOE_UK/status/1107669188665982977 The speaker pointed out that the precedent had been put into action 12 times before 1920, noting that it had not been required since then as governments had not breached it. Last week, MPs voted overwhelmingly to extend the Article 50 process of leaving the EU. That instructed May to seek a delay to the initial March 29 deadline, which requires all member states to agree on a fresh exit date. Bercow had been criticised leading up to last week's votes for blocking an amendment that ruled out a second referendum on Brexit, having allowed MPs to vote on whether or not to hold one.