A referendum on the UK’s exit package from the European Union – with the option to remain a member of the bloc – should be held before the Government triggers Article 50, a Labour MP is demanding in a private members’ bill.

The bill from Geraint Davies, the Labour MP for Swansea West, comes as the Supreme Court prepares to hand down a crucial ruling on whether MPs should be given a vote on the triggering of Article 50 of the Lisbon Treaty – the mechanism for leaving the EU.

But Mr Davies’ bill, which is not official Labour policy, calls on the Government to set out its negotiation package and allow the UK electorate to vote on this in a referendum before Theresa May serves EU leaders with the Article 50 notice.

“In June’s referendum, the British people did not vote for particular terms of the UK’s withdrawal from the EU,” said Mr Davies. “Triggering Article 50 hands back our EU membership, and gives the remaining 27 EU member states two years to decide the exit package which best suits their interests, to discourage others from leaving.

“The assurance that the UK would give people the final say on the exit package through a referendum would give the EU an incentive to negotiate before Article 50 is triggered. The vote would have an option to remain in the EU, if that is preferable to the agreed exit package. The Government should therefore delay triggering Article 50 and give people the final say.”

The Terms of Withdrawal from EU Referendum Bill says that the Government should also include “detailed and specific information” on the proposed status of EU nationals living in the UK and UK citizens living in other member states. Since the referendum in June, their status has been in a state of limbo.

The Bill proposes to ask the British public: “Do you support the Government’s proposed United Kingdom and Gibraltar exit package for negotiating withdrawal from the European Union or Should the United Kingdom remain a member of the European Union?”

The options will include “support the Government’s propose exit package” and “remain a member of the European Union”.

In the landmark ruling on Tuesday the Supreme Court will deliver the verdict of 11 judges. It follows a ruling by the High Court in November stating that Parliament should have the final say on officially deciding that the UK wishes to leave the EU. Businesswoman Gina Miller, the lead claimant in the High Court case, has insisted the legal action was not aimed at stopping Brexit, but ensuring the supremacy of Parliament in the process.

But Mr Davies’ bill is unlikely to halt the Article 50 process, considering Jeremy Corbyn, the Labour leader, has stated on several occasions he will not block legislation allowing Ms May to trigger it. It is not year clear, however, whether MPs in the party will be compelled to vote for the measure as the leader’s team will not reveal if the vote will be whipped until the Government’s legislation appears in the Commons.

Supreme Court Brexit Challenge Show all 13 1 /13 Supreme Court Brexit Challenge Supreme Court Brexit Challenge People wait to enter the public gallery outside the Supreme Court ahead of the challenge against a court ruling that Theresa May's government requires parliamentary approval to start the process of leaving the European Union, in Parliament Square, central London Reuters Supreme Court Brexit Challenge Gina Miller, co-founder of investment fund SCM Private arrives at the Supreme court in London on the first day of a four-day hearing Getty Supreme Court Brexit Challenge A man waves the EU flag in front of the Supreme Court Getty Supreme Court Brexit Challenge Satirical artist Kaya Mar poses with two of his paintings in front of the Supreme Court Getty Supreme Court Brexit Challenge Pro-Europe protestors dressed as Supreme Court Justices stand outside the Supreme Court ahead of the first day of a hearing into whether Parliament's consent is required before the Brexit process can begin. The eleven Supreme Court Justices will hear the government's appeal, following the High Court's recent decision that only Parliament can trigger Article 50 Getty Supreme Court Brexit Challenge The eleven Supreme Court Justices will hear the government's appeal, following the High Court's recent decision that only Parliament can trigger Article 50 Getty Supreme Court Brexit Challenge Businesswoman Gina Miller arrives at the Supreme Court ahead of the first day of a hearing into whether Parliament's consent is required before the Brexit process can begin Getty Supreme Court Brexit Challenge Attorney General Jeremy Wright arrives at the Supreme Court in London EPA Supreme Court Brexit Challenge Protesters outside the Supreme Court in London, where the Government is appealing against a ruling that the Prime Minister must seek MPs' approval to trigger the process of taking Britain out of the European Union PA wire Supreme Court Brexit Challenge A protesters wearing a judge's wigs and robes stands outside the Supreme Court ahead of the challenge against a court ruling that Theresa May's government requires parliamentary approval to start the process of leaving the European Union, in Parliament Square, central London Reuters Supreme Court Brexit Challenge A protester holds up a placard outside the Supreme Court ahead of the challenge against a court ruling that Theresa May's government requires parliamentary approval to start the process of leaving the European Union, in Parliament Square, central London Reuters Supreme Court Brexit Challenge Pro-Europe protestors dressed as Supreme Court Justices stand outside the Supreme Court Getty Supreme Court Brexit Challenge A man waiting to enter the public gallery waves a European Union flag outside the Supreme Court ahead of the challenge against a court ruling that Theresa May's government requires parliamentary approval to start the process of leaving the European Union, in Parliament Square, central London Reuters