Counting the uncountable
It makes little sense to treat major Acts of Parliament such as the 457-page Health and Social Care Act 2012 which reformed the whole NHS the same as, say, three pages of technical regulations on VAT fraud.
The House of Commons Library has warned that "there is no totally accurate, rational or useful way of calculating the percentage of national laws based on or influenced by the EU."
So no set of figures can give us a good measure of the influence of the EU on law in the UK.
It’s more meaningful to look at specific sectors and areas of law.
In agriculture, fisheries, external trade, and the environment, it’s fair to say that EU legislation and policy is indeed the main driver of UK law and policy, although the UK retains some freedom of action in these areas.
Estimates range from 13% to 65%, although all have problems
In 2010, the House of Commons library published a comprehensive analysis of the variety of ways this percentage can be calculated. There are difficulties with all measurements, but it concluded "it is possible to justify any measure between 15% and 50% or thereabouts".
The figures depend on which UK law is included in the calculation, and the extent of 'EU influence' that we look at.
There’s no single definition of ‘UK law’. Rules made by judges have the force of law, for example, but counting them up is probably impossible.
Setting those aside, the main types of laws in the UK are Acts put in place by the UK Parliament, rules and regulations drawn up by ministers known as Statutory Instruments, and regulations produced by the EU which apply automatically.
An estimated 13% of Acts and Statutory Instruments have an EU influence, whereas that rises to 62% when EU regulations are included in addition to Acts and Statutory Instruments.
The other thing to bear in mind is that in areas for which the EU is responsible, EU laws override any conflicting laws of member countries. So there’s an overall influence in these areas that is harder to count.
Calculating the 13% figure
The first method takes UK Acts and Statutory Instruments which put in place, or refer to, things the UK has to do under EU law.
This varies from ones which make only a passing reference to EU obligations to ones where the main purpose is to implement EU obligations.
The House of Commons Library found that between 1993 and 2014, 13% of these two types of law were EU-related, on average.
13% is likely to be too low, in reality, but 62% is much too high
This first method doesn’t consider all legal influence that the EU has on the UK. Some EU initiatives don’t need to be made into laws at a national level as they are implemented through 'EU regulations'.
EU regulations automatically have binding legal force in every EU member country. The important ones are usually agreed by government representatives on the EU’s Council, as well as by the directly elected European Parliament.
Some of these are important: big businesses considering a merger will need to know a lot about the EU Merger Regulation, for example.
Many others are relevant but highly technical: assigning a customs code to light-up plastic skulls, or the regular calculation of the ‘standard import value’ for fruits and vegetables. They’re made by the European Commission on its own, without going through the main lawmaking process.
These kinds of decisions are more like what a civil servant or even a local council might decide in the UK, which reflects the fact that the Commission isn’t like any one UK government body. Its output consists both of important laws and proposals for laws, as well as mundane administrative decisions.
So while leaving EU regulations out of the count of ‘UK laws’ is likely to underestimate EU influence, including them is likely to overestimate it.
Legal experts have described this method as “comparing apples with pears”. As many of these are administrative decisions passed in the forms of laws, you could compare them to all the decisions made in government departments rather than Acts and Statutory Instruments passed by parliament.
All this goes to show the difficulties of these counting exercises in the first place.
Mix-ups with the European Parliament
Sometimes a figure of 70% has been used, including in 2014 by Viviane Reding, then Vice-President of the European Commission. But her office told us that she meant the percentage of EU laws that the European Parliament and the Council have had an equal say on. The EU now says it’s “about 80%”.
The rest, her office said, are either decided solely by the Council, or with Parliament giving the Council consent to them being passed.
This isn’t counting regulations passed by the European Commission.
The official position of the European Parliament is that "a big portion of the laws adopted by the House of Commons and House of Lords actually are EU-laws that are made into national laws by the national parliaments". When we asked for its source, the Parliament cited the House of Commons Library research discussed here, as well as examples from elsewhere in Europe.
Update 6 June 2016
We revised and updated this article from an earlier version published in April 2014.