The looming meaningful vote on Theresa May’s EU withdrawal deal avoids the Prime Minister pressing ahead with Brexit without agreement from a majority of MPs.
The action is designed to maintain Parliamentary sovereignty over the Government by preventing unpopular changes being steamrollered through following the narrow EU referendum result in June 2016.
This concept has a long and complex history, starting when the Government unilaterally invoked Article 50 on March 29 2017, setting a two-year deadline for completion of Brexit negotiations.
Remain campaigner Gina Miller challenged the Government at the High Court, insisting Parliament should have voted before Article 50 was invoked.
Ms Miller won her case, with judges ruling that authorisation by Parliament was required for the invocation of Article 50, a decision which was also upheld by the Supreme Court on appeal.
As a result, Mrs May confirmed she would put the final Brexit deal to a vote in both Houses of Parliament before any Brexit deal came into force.
However, it remained unclear whether the vote on the deal would be “meaningful”, by allowing MPs to reject Mrs May’s deal, or if it would be merely rubber-stamping a deal – potentially after Brexit had happened.
The baton for parliamentary sovereignty was picked up in the Commons by Tory MP and former attorney general Dominic Grieve in December 2017, when he sought to get a “meaningful vote” on Mrs May’s deal put into law.
After strong resistance from then-Brexit secretary David Davis and some parliamentary ping-pong, the Government conceded the point and the Withdrawal Agreement Bill containing the requirement for a meaningful vote passed into law on June 26 2018.
So, when Mrs May brought her Brexit deal to Parliament in November last year, a meaningful vote on the deal was scheduled for December 11.
However, after three days of debate in the run-up to the vote, Mrs May pulled the vote the day before it was due because she was facing defeat and appealed for more time to come back with improvements.
The vote has now been rescheduled for the week beginning January 14 – but another delay or a change in direction looks increasingly likely given the unpopularity of Mrs May’s deal.
If the Government is defeated, ministers have 21 days to make a statement to the House of Commons setting out how it plans to proceed and a fresh vote on those plans must take place within seven days.