To deliver Brexit the Government had to undertake the largest legislative exercise ever in the UK. The burden of this exercise was borne by the system of delegated legislation — via the delegation of powers to ministers in Acts of Parliament and then through the making of regulations (in the form of Statutory Instruments (SIs)), using the powers conferred in those Acts.

The Government had first to create a UK legal order that could operate independently of the EU — initially after ‘exit day’, and then, after the Withdrawal Agreement was secured, after the end of the transition period. The 2018 EU (Withdrawal) Act saved EU law as a new category of UK law, and then ministers used SIs to address ‘deficiencies’ in that body of ‘retained EU law’ to make it work in a UK-only context.

In parallel, ministers have legislated through a series of Acts in areas as varied as customs, sanctions, agriculture, fisheries and immigration, creating powers to provide for UK policy beyond the end of the transition period. Both the EU (Withdrawal Agreement) Act 2020 and EU (Future Relationship) Act 2020 also gave ministers extremely broad powers to implement the Withdrawal and future relationship treaties with the EU.

The nature of the Brexit process lent itself to the use of delegated legislation: there was a need to elaborate complex and technical detail, deploy flexibility and adaptability, and act quickly in times of crisis.

But the conjunction of some of the broadest, most constitutionally-important powers ever seen on the statute book with inadequate scrutiny of the ways these powers might be exercised has constituted a toxic mix for the balance of power between executive and legislature, driving a coach and horses through the core principle of accountability of Government to Parliament.

Most of the Brexit Acts and Bills still to be passed are ‘skeleton’ ones in which, in the words of three House of Lords select committee chairs, “broad delegated powers are sought in lieu of policy detail”. Such Bills are problematic, because Parliament is asked to approve powers without knowing how they might be used, and because the true impact of the provisions is unknown. The majority of the legislative content — both principle and policy — will be left to delegated legislation. But this legislation, in the form of SIs, will attract only limited parliamentary scrutiny, especially in the House of Commons.

By the end of 2020, ministers had laid around 960 Brexit-related SIs before Parliament. The powers in the various Brexit Acts will mean more are laid in 2021 and beyond. These SIs are not amendable. Many are subject to the ‘negative procedure’ and so do not require active parliamentary approval; most of these are ‘made’ — that is, they are already ‘laws’ — before they are laid before Parliament, and can be brought into force before parliamentary scrutiny is complete. There is no guarantee of a debate if an MP objects to a ‘negative’ SI, as the Government decides whether to allocate time for consideration. Most ‘affirmative’ SIs, which require active debate and approval, usually by both Houses, are considered in often-perfunctory meetings of delegated legislation committees, where MPs are appointed by the whips, which have no dedicated parliamentary staff, and where decision takes place on the basis of a pointless ‘consideration’ motion before the formality of approval by the whole House.

Despite the exceptional nature of the Brexit legislative exercise, only one limited reform of this delegated legislation scrutiny process has been secured. The European Statutory Instruments Committee (ESIC) can review negative SIs laid using powers in the EU (Withdrawal) Act 2018 and recommend they be upgraded to the affirmative procedure. It is a toothless advisory body bolted onto inadequate scrutiny procedures.

In practice, coronavirus may have a greater impact than Brexit in pushing a sufficiently large number of MPs finally to demand reform of the process. Disquiet over the slew of lockdown and other coronavirus-related measures being implemented through SIs, often at very short notice, saw Conservative backbenchers threaten rebellion in the face of government by ‘diktat’. The combination of Brexit and coronavirus has also significantly raised media and public awareness of the inadequate and undemocratic nature of the system.

Now the transition has ended, some factors might be helpful for a delegated legislation scrutiny reform effort. As MPs move through 2021, the most acute phases of both Brexit and the pandemic will be over, potentially freeing up some parliamentary attention. The claim that the Government must act through SIs because it needs to make law quickly will fall away.

Most importantly, the scope of the post-Brexit policy making that the Government will be able to carry out through SIs is likely to be even more fully exposed, as the Government uses its new powers to develop the UK’s post-Brexit statute book. The ongoing use of SIs to enact legal divergence between Britain and Northern Ireland could be particularly controversial, as could their use to constrain the pursuit of policy choices by the Scottish and Welsh devolved administrations that differ from those of the UK Government.

However, its concession over the process for major lockdown SIs notwithstanding, the Government has shown no signs of wishing to pursue reform. Indeed, it appears to have a strongly majoritarian concept of Government, in which constraints on an administration with a House of Commons majority are largely to be resisted. The Government’s control of the Commons’ time, legislative agenda, and Standing Orders make it extraordinarily difficult to advance changes. The Opposition, with an eye on the prospect of forming a future Government, are content to criticise but not to advance reforms which may circumscribe their future legislative powers. And, despite Conservative backbenchers’ success in forcing minor concessions over lockdown SIs, there is little sign yet of the necessary coalition of MPs willing to devote significant political capital to a thoroughgoing reform of the delegated legislation system.