The lynchpin of the British constitution is that the government sets the agenda for the House of Commons on a daily basis. The pressures of resolving the British exit from the EU have now seen MPs take control of the legislative business on Wednesday. When the house voted to set its own terms, a senior former cabinet minister Sir Oliver Letwin was asked by the Speaker John Bercow to propose a motion for the day. Amendments to that motion will also be selected by Mr Bercow. The aim is to give the parliament a menu of options through a series of votes that would instruct Downing St on how to proceed. A clear outcome would hopefully end the stalement that has engulfed Prime Minister Theresa May's Withdrawal Agreement signed in Brussels late last year. The official date of Brexit has shifted from Friday, March 29 to an alternative timescale. If MPs decide in the end to back Mrs May's deal as a platform for negotiating a new relationship with Europe, London will leave on May 22 at 11pm local time. In the absence of an alternative proposal -- Mrs May called the option a slow Brexit -- Britain will be forced to leave on April 12 at 11pm. An alternative proposal, which could include a second referendum that could cancel the 2016 vote, would mean a longer delay and a much closer long-term relationship with Europe. Yet another option would be to cancel Brexit by revoking the Article 50 clause in the EU constitution. That would leave Britain as a full member of the EU and the Brexit debate would come to a swift halt. Few members of parliament were willing to guess how the voting will go on Wednesday. However it does appear to coincide with a shift in public opinion and for the first time since 2016 the idea of remaining inside the EU has a commanding lead in opinion polls. John Curtice, the country's leading polling expert, said the mood of the country had changed as the wrangling after the referendum had dragged on. "The longer the Brexit process has gone on, the more critical and pessimistic voters have become," he concluded.