London: Coming as a setback for British Prime Minister Theresa May, Rebel Tory MPs on Wednesday joined forces with Labour to announce that May has to come up with fresh plans within three sitting days if her Brexit deal is rejected by MPs the next week. Also Read - Brexit: New Split on State Aid Further Derails Negotiations Between Britain, European Union

May postponed an initial vote last month in the face of opposition from all sides of the House of Commons, but has now set it for next Tuesday evening after 1900 GMT, following five days of the debate starting Wednesday. Also Read - Scotland, Wales Worry as UK Plans to Withhold State Aid After Brexit Transition

May is still struggling to convince both opposition lawmakers and her own Conservative party to back the divorce agreement, heightening fears Britain could leave the European Union on March 29 without a deal. Also Read - Brexit: 'Wish to Establish Ambitious Ties With UK But Need to Iron Out Details,' Says EU

She has promised to secure further assurances from the EU on the most controversial elements of the Brexit deal relating to Northern Ireland, and has held talks with European leaders in recent days.

“The work to secure those assurances is ongoing,” her spokesman said, adding that the prime minister hoped to have something to offer MPs before next week’s vote.

May is hosting several drinks parties for lawmakers this week in a bid to win them round, arguing her deal is the best compromise that ends EU membership while protecting jobs.

Environment Secretary Michael Gove told cabinet colleagues that critics holding out for a better deal were like swingers in their mid-50s waiting for Hollywood star Scarlett Johansson to turn up on a date.

But with opposition among MPs still strong, there is growing speculation London could seek to delay the EU’s two-year Article 50 exit process to allow more time to get the deal through parliament.

A source in Brussels told AFP several weeks ago that Britain has been discussing the possibility with European officials, and a junior British minister, Margot James, publicly voiced the idea on Monday.

But May’s spokesman insisted: “We will not be extending Article 50. “There are people in the European Union who are discussing this issue, but that is not the position of the UK government.”

The other 27 EU leaders have repeatedly said they will not reopen the deal struck with Britain in November, which covers key separation issues such as money and expatriate citizens’ rights.

But they issued a joint statement at an EU summit last month emphasising the temporary nature of the so-called backstop arrangement designed to keep open the UK border with Ireland after Brexit.

And Irish Prime Minister Leo Varadkar told the Irish Times there were discussions on whether the EU could offer “a further set of written guarantees, explanations and assurances”.

The backstop would keep open the border between British Northern Ireland and EU member Ireland after Brexit by temporarily aligning Britain with EU trade rules.

Eurosceptic Conservatives and Northern Ireland’s tiny Democratic Unionist Party (DUP), which props up May’s government, fear it could tie London to Brussels for years to come.

However, France’s Europe Minister Nathalie Loiseau said “there is nothing more that we can do” — and warned against putting too much faith in talk of extending Article 50.

“I don’t work on hypotheses — the current situation is complex enough… Let’s stick to where we are now,” she added.

An EU diplomat also told AFP that the idea of delaying Brexit “is a very hypothetical option”.

Any extension to Britain’s departure would be complicated by the elections to the European Parliament in May. After Brexit, it will no longer be represented in the assembly.

May is looking at a possible time limit to the backstop arrangement and increased parliamentary scrutiny to try to sway MPs. But if her efforts fail, many fear Britain could leave the EU with no deal, with potentially disastrous legal and economic consequences.

A cross-party group of MPs sought Tuesday to amend a finance law to limit the government’s tax-raising powers in the event of “no deal”, as a way of forcing it to stop such a scenario.

The impact of a disorderly Brexit would also be felt across Europe, including in the EU budget. May’s deal sets out plans for a post-Brexit transition period in which Britain would keep making financial contributions until December 2020.

EU budget commissioner Gunther Oettinger said that without this, “we would be short a figure in the billions of euros for the rest of the year and a higher figure for 2020”.

(With PTI inputs)