On 13 March the UK government tabled a motion to determine whether the House of Commons wished to rule out a "no deal" Brexit on 29 March. By a narrow margin of 4 votes the government's motion was amended to make it clear that the House of Commons wished to rule out "no deal" not just on 29 March, but at any time. The government then issued an instruction to Conservative party MPs to vote against the amended motion. Despite that, the amended motion passed with an increased majority of 43.

The resolution might express the wishes of a majority in the House of Commons, but it does not override the default legislative position, which is still moving inexorably towards a "no deal" Brexit on 29 March. Urgent legislative action is required to amend the EU (Withdrawal) Act 2018 so that it no longer specifies 11.00pm on 29 March as "exit day" whether or not there is an approved Withdrawal Agreement and Political Declaration (WA).

The government's immediate response to the 13 March vote was to table a somewhat convoluted motion for 14 March. Under that motion, the government would seek a "technical extension" of the Article 50 notice period, effectively moving "exit day" to 30 June. However, that extension would be sought only if the House of Commons has approved the WA by 20 March, enabling the government's request to be made at the European Council meeting scheduled for 21-22 March. If the WA has not been approved in time, then the government would have to seek a longer extension, with the risk of veto by one or more EU Member States, with the renewed risk of "no deal".

A striking feature of the government's 14 March motion is its strong indication that the government will bring its WA back to the House of Commons for a third time. The WA was rejected on 15 January by 230 votes. It was rejected again on 12 March by 149 votes. Faced with the impending prospect of a "no deal" Brexit, the government's calculation appears to be that a third vote might succeed.

The government's plan is likely to face procedural challenge. MPs have been poring over Erskine May (the "bible" of UK Parliamentary procedures) and have located (on page 397) a convention that if a motion has been defeated then that motion cannot be brought back for a further vote during the same session of Parliament. The 12 March vote did not breach that convention because the government had brought back from Strasbourg additional provisions and clarifications. However, MPs are likely to press the Speaker of the House of Commons to rule out a third vote if the WA is essentially the same as the version rejected on 12 March.

It would be for the Speaker to decide whether to allow a third vote on the WA. It would also be open to the government to call a vote on whether the House of Commons should override the relevant convention, given the serious nature of the question. Alternatively, the government might seek to establish that the motion is substantially different from that considered on 12 March – possibly by introducing amended or additional legal advice concerning Article 62 of the Vienna Convention. In any of those events, arcane procedure and fine semantic differences might determine whether the government is able to launch a third attempt to secure approval for its WA.

The next steps in the process is the vote, scheduled for 17.00 on 14 March, on the government's motion concerning a possible extension of the Article 50 notice period. That motion may be amended, and it is for the Speaker to decide which (if any) amendments are put to the vote. However, the government's evident determination to call a third vote on the WA means that Brexit uncertainty may well continue throughout the remaining 15 days to "exit day".