In the immediate aftermath of defeat by a margin of 230 votes, Prime Minister Theresa May observed that while it was clear that the House of Commons did not want her Withdrawal Agreement, it was not clear what it did want. As attention shifts to the vote of no confidence in the government, scheduled for the evening of 16 January, the risk of a "no deal" Brexit remains live. The scale of the government's defeat on 15 January exceeded predictions, and perhaps oddly seems to have convinced both those who favour a "no deal" exit and those who favour either a softer Brexit or a further referendum that the momentum is in their favour. From a legal perspective, however, "no deal" remains the default position, avoidable only by clearly drafted primary legislation. Consequently, as the Parliamentary drama continues to develop, Brexit preparedness and resilience remains an urgent priority for business.
No deal – the default
To avert defeat in a series of votes during 2018, the government accepted a number of amendments to the EU (Withdrawal) Act 2018 and to other legislation, including the Taxation (Cross-Border Trade) Act 2018. The result is that provisions directing a "no deal" exit are scattered through that primary legislation. Perhaps the most significant amendment (though not the only one that would have to be addressed and overturned) is the definition of "exit day" in the EU (Withdrawal) Act. That definition, which specifies 29 March, attaches to a number of key provisions, which together mean that the UK would leave the EU with or without a deal.
The EU (Withdrawal) Act 2018 is primary legislation. It cannot be overridden by a mere resolution of the House of Commons. Nor (being a constitutional statute) is it subject to the doctrine of implied repeal. Its provisions can be reversed only by new primary legislation, explicitly drafted to repeal and replace it.
The EU (Withdrawal) Act 2018 would also remain stubbornly in place if the government were to seek an extension to the Article 50 notice period. Even if the EU were to agree to an extension, those who advocate a "no deal" exit would undoubtedly argue that, taken together, the 2017 Act which authorised the UK's Article 50 notice and the 2018 Act which set the exit day, would have to be amended before any such agreement could be effective. In that context, the Supreme Court ruling in Miller v Secretary of State  UKSC 5 becomes an authority favouring the "no deal" argument.
Jeremy Corbyn tabled a vote of no confidence in the government immediately after the government's defeat on 15 January. The Democratic Unionist Party (DUP) immediately confirmed that they would resume their support of the government in that vote, leading to predictions that the government will survive. While that might remain the likely outcome, it is not the only possibility.
Following the decisive rejection of its Withdrawal Agreement, the government is under pressure to find some form of deal that could command a majority in the House of Commons, or as a last resort to agree to a further referendum. From the perspective of a "no deal" advocate, the risk must be that some form of accommodation might be found, leading to a "soft" Brexit or a "Brexit in Name Only". Faced with that prospect, it might be tempting to trigger a sequence of events that may offer the only viable route to a "no deal" Brexit.
DUP support would not be enough to save the government from a backbench rebellion. If those who most passionately advocate a "no deal" exit were to abstain or even vote against the government, there would be a risk of defeat. In that case, there would be a 14 day period within which the government would have to find a new majority, or a new government would have to be formed. Failing that, the Fixed Terms Parliament Act 2011 provides that there would be a general election.
If a general election were to be triggered, then Parliament would be prorogued and then dissolved, In effect, there would be no body capable of enacting legislation to overturn the "exit day" built into the EU (Withdrawal) Act 2018. Party, and media, attention, would undoubtedly shift to the drama of an election, the earliest date for which would produce a new government with only days to spare before 29 March.
Pre-empting the "no deal" tactic?
Just before the final day of debate on the government's Withdrawal Agreement, Nick Boles MP secured first reading for his Bill designed to avert a "no deal" outcome. The Bill's second reading was requested for 16 January, but it was superseded by the vote of no confidence, and unless scheduled as part of the government's business statement on 17 January its slot in the Parliamentary timetable will remain uncertain.
In practice, averting a "no deal" outcome would require concerted cross-party action, facilitated by the government, before Parliament is prorogued and dissolved should an election be triggered. However absorbing and distracting the political drama might be, only close and sustained attention to legislative detail can avert an accidental or engineered "no deal" Brexit on 29 March.