The U.K. government has officially rejected a petition with 5.8 million signatures calling for the cancellation of Brexit, saying ignoring the popular mandate of 2016 would “undermine both our democracy and the trust that millions of voters have placed in Government.”

The petition, along with a million-strong protest march in London, Saturday, was a last-ditch effort by U.K. citizens opposed to the country’s exit from the European Union, which was set for Friday — though now potentially delayed until at least April.

Britain’s parliament is yet to approve a way forward. Prime Minister Theresa May’s Brexit deal — which includes a two-year transition period, during which the U.K. and EU could negotiate their future trading and regulatory arrangements — remains unapproved, having been voted down twice in Parliament.

The House of Commons will begin voting on potential alternatives throughout Wednesday, while May is likely to ask Parliament to consider her deal for a third time later this week. If the deal finally passes, the U.K. will leave the EU on May 22. If it’s rejected for the third time, the British government will have until April 12 to propose an alternative solution to the EU.

In a significant move, leading pro-Brexit MP Jacob Rees-Mogg said Tuesday that he is willing to back May’s Brexit plan if she pledges to resign ahead of the trade negotiations. Former London Mayor Boris Johnson also implied Tuesday that he could back the deal on the same terms: “If we vote it down again there is an appreciable and growing sense we will not leave at all,” he said.