How conspirators will change rules – then seize control

If Mrs May’s deal were to be voted down tomorrow, she is required – under the Grieve amendment controversially allowed by Speaker John Bercow last week – to return to the Commons on Monday week to make a statement.

By the end of next week she will put before the Commons a motion setting out her plan. It would be amended by Labour and rebel Tory MPs to change the standing orders of the Commons – the rules of how Parliament works.

If the Speaker approved – and Parliament agreed – backbenchers would seize power over proposals for new legislation and then submit a single Brexit Bill.

The Bill would give Mrs May 21 days to come up with an alternative plan which commanded the support of a majority of MPs.

If she failed, the liaison committee would then be made responsible for coming up with a new proposed deal. This is made up of 36 select committee chairmen and is dominated by Remainers. It is led by Tory Sarah Wollaston, a campaigner for a second referendum.

The liaison committee would draw up a new Brexit plan and vote on it. If agreed by a majority of the committee, it would go before Parliament – and if MPs approved it the Prime Minister would be tasked with renegotiating along those lines.

The new deal, if negotiated with the EU, would come back before the Commons and Lords for a vote.

Ministers would be put under a legal duty to extend Article 50 to allow time for the negotiation.

If no deal was done by March 27 and the EU refused an extension to Article 50, it would be revoked.