The projected volume of Brexit SIs has evolved considerably over the last 18 months, although there has been a noticeable lack of clarity about whether some SIs will be required for a ‘no-deal’ scenario only, or whether some will be needed for all potential eventualities. During the passage of the EU (Withdrawal) Act 2018, ministers stated that they expected to lay between 800 and 1,000 Brexit SIs to prepare the statute book for exit day, with the final figure perhaps closer to 800. In November 2018, this figure was revised down to approximately 700 Brexit SIs (pdf), and in December the number was again revised to ‘fewer than 600’.

However, ministers have never been clear about how many below 600 the projected number of Brexit SIs might fall. It is possible that the total number of Brexit SIs may prove to be nearer 500 than 600, for the flow of Brexit SIs has rarely matched the government’s projections.

In a letter to the parliamentary SI sifting committees on 25 October 2018 (pdf), DExEU minister Chris Heaton-Harris MP laid out the broad ‘projected flow’ of SIs anticipated each month from October 2018 to March 2019. The lower end of these projections suggested a potential total of 410 Brexit SIs might be laid; the upper end of the projections suggested the total could be as high as 700.

In practice, the total number of SIs laid each month has been closer to the lower end of these projections. During the months of October to January, 328 Brexit SIs were laid; the government’s lower-end projection for these months was 400, while its estimated upper limit was 600. In January alone, 81 Brexit SIs were laid (of which 24 were laid on the last day of the month); ministers had previously indicated that they expected to lay around 100 SIs during that month.

For February and March, the minister's 25 October letter (pdf) suggested that between 10 and 50 SIs would be laid each month. The clear implication was that the number of SIs would taper off the nearer we got to exit day. If the government really is aiming to lay close to 600 Brexit SIs in total, it will have to lay almost 100 -- nearly double its high-end projection -- in each of February and March.

The vast majority of SIs laid before Parliament will be subject to one of two types of scrutiny procedure. SIs that are subject to the negative scrutiny procedure do not require a debate or vote in both Houses before they can become law. In contrast, those that are subject to the affirmative scrutiny procedure must be debated and formally approved by both Houses before they can become law.

In normal parliamentary sessions, negative SIs constitute about 75% of all SIs laid before Parliament. But, in contrast to this pattern, the majority -- 54% -- of Brexit SIs laid so far are subject to the affirmative scrutiny procedure. This is partly because of the scrutiny safeguards built into the EU (Withdrawal) Act 2018, and partly because of the sifting process the Act introduced, which enables parliamentary sifting committees in both Houses to recommend that proposed negative SIs produced under the Act should be upgraded to the affirmative procedure.

Negative SIs are subject to a 40-calendar-day scrutiny period during which either House can, in theory, object to them. However, negative SIs routinely come into force before their 40-day scrutiny period expires: in the 2015-16 parliamentary session, for example, this applied to 80% of negative SIs laid before Parliament. However, under a separate 21-day rule, the government is supposed to leave 21 calendar days between laying a negative SI and bringing it into force. If this rule is to be respected, negative Brexit SIs will need to be laid by 9 March to come into force by 29 March. Much will depend on how far the government and parliamentarians are prepared to let ‘best practice’ understandings about parliamentary scrutiny slide. But, ultimately, the weak nature of parliamentary control for negative SIs means the government can get these SIs onto the statute book by exit day.

For affirmative SIs, in the House of Commons, Delegated Legislation Committees (DLCs) normally debate an SI before the approval vote is held in the Chamber on a subsequent day. SIs can also be debated in the Chamber, with the approval vote taking place immediately after the debate. The House of Lords must also debate affirmative SIs in Grand Committee or in the Chamber.

As of 12 February, debates in the House of Commons have been held or scheduled for only 115 of the 221 affirmative Brexit SIs laid so far. This week (starting 11 February), MPs are debating 10 Brexit SIs, but this still leaves a backlog of 106 debates of up to 90 minutes each that have yet to be organised. This means an average of 18 Commons debates per week need to be held each week through to exit day on 29 March. This backlog of debates that the government needs to schedule for affirmative SIs is the biggest challenge ministers face in managing the SI programme between now and exit day.

Furthermore, if a majority of the up-to-200 Brexit SIs that have not yet been laid before Parliament are also subject to the affirmative procedure, the number of debates needed will rise proportionately.

Besides the optics of not going into recess when the country’s future outside the EU is not yet resolved, Brexit SI management is where cancelling the February recess particularly helps the government. Ministers now have a few more sitting days on which they can both lay SIs and schedule debates. While scheduling all these debates will test the skills of the government’s business managers, it can be done.

Ultimately, if the government is running out of time, it can initiate the urgent case procedure set out in the EU (Withdrawal) Act. Under this procedure, ministers can make SIs that come into immediate effect having been ‘made’ (signed-off) by the minister. ‘Made affirmatives’ require both Houses to approve them within 28 days to remain in force.

To use this procedure, ministers will simply have to provide a written statement explaining the urgency. In the circumstances, this will not be difficult. Ministers have said that they do not anticipate using the urgent procedure – and if our hunch is correct, and the overall number of Brexit SIs that still need to be laid is lower than expected, they may not need to do so. Nevertheless, it is a useful insurance in the event of problems arising on or near 29 March. This procedure would ensure that all SIs that are required can come into effect on exit day.

An edited version of this article can also be found online at Prospect Magazine.