As she began outlining her vision for Brexit at the Conservative Party conference, Prime Minister Theresa May stated her intention to propose a “great repeal bill” to replace the European Communities Act – the main law governing the application of EU law in the UK.

This is a very important move that marks the beginning of the end of EU law being automatically applied in the UK. That makes it important for British citizens to keep an eye on how the government handles the repeal bill. Will there be sufficient democratic scrutiny of changes that will affect practically every aspect of British life?

Despite its title, the act won’t actually repeal any substantive EU law at all. In fact, it will do just the opposite: it will keep all pre-Brexit EU law in force in the UK. After leaving the EU, the UK can then go through all the laws once covered by the European Communities Act and decide which it wants to keep and which it wants to discard.

The bill will probably be passed as an act of parliament in 2017, but it won’t take effect until Brexit day – which will probably be in spring 2019. That’s because the UK still has to comply with EU requirements until it actually leaves.

But this doesn’t mean that the law will be meaningless. It will prevent post-Brexit EU law from applying to the UK automatically as an EU member state. It will overturn the current rule of EU law “supremacy”, which gives EU laws priority over all other UK laws. It will end the jurisdiction of the EU courts in the UK. And it will provide a system for removing or amending EU laws which apply to the UK – which is the opposite of what the current law does.

The bill also offers a degree of legal certainty at a difficult time. Businesses will be reassured that Brexit will not suddenly create a legislative vacuum for a big chunk of the law, such as intellectual property and environmental protection.

But it won’t bind the European Union to anything. If the UK decides to keep any existing laws that relate to trade, or any other relations with the EU, it will have to be agreed by both parties before having any practical effect.

Who is in charge?

One crucial matter looks set to dominate debate over the bill, and will certainly dominate its application in practice. This is the process for repealing or amending particular EU laws retained by the act as and when the UK wishes to do so. The key issue here is whether the government or parliament should decide what to keep. This is part of a broader debate on the respective roles of the executive and parliament during the Brexit process.

The government has made it clear that it wants to make at least some of the key decisions without putting them to a parliamentary vote.

Acts of parliament need to be approved by both the House of Commons and the House of Lords, following a process of several readings where there is a chance for public input and amendments. So the government may need to push through the changes it wants as “secondary legislation” – these cannot usually be amended by parliament (either of the two houses can veto draft secondary legislation, but this is rare).

Using secondary legislation to repeal EU laws would be controversial because it would remove parliament from the process. Secondary legislation was often used in the past to put EU law into place and was criticised for this very reason. Using secondary legislation to overturn or amend those EU laws exacerbates the problem.

The government’s negotiation of important EU laws was at least always scrutinised in depth by parliament, whereas there is no such level of scrutiny for the adoption of secondary legislation in the UK – unless some special rules, involving some form of effective parliamentary scrutiny and amendment, are developed.

The government may also seek powers not only to fast-track the repeal of EU laws which apply in the form of secondary legislation, but also those which apply in the form of acts of parliament – such as workers’ rights. This process is particularly controversial as it involves the government directly amending an act of parliament, which then becomes known as a “Henry VIII clause” because it has bypassed parliamentary scrutiny.

In my view, such clauses should be rejected for the post-Brexit process as a matter of principle. If an EU law issue was deemed important enough to enshrine in an act of parliament while the UK was a member, it should be for parliament to repeal or amend it once the UK has left.

Laws on workers’ rights and the environment, given their particular importance, as well as other issues where parliament usually plays the main role, should only be changed by acts of parliament. The government says it doesn’t wish to weaken workers’ rights; ensuring they could only be weakened by act of parliament would put that promise into practice.

Overall, then, the great repeal bill won’t tell us what Brexit is. That will depend partly on which EU laws are repealed after Brexit day and what relations look like with the EU thereafter. But it is a significant part of the legal Brexit process so the British public should keep a close eye on developments to make sure the government is held to account.

Steve Peers does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

This article was originally published on The Conversation. Read the original article.