This page comes from the Confederation of British Industry (CBI) Business Assessment of EU Reforms document published in February 2016,
It shows a dramatic decrease which suggests that the European Commission is taking seriously the need to reduce red tape and focus on helping business growth. However, many would point out that does not tackle the underlying problem of lack of accountability for those making European rules, nor does it say anything about reducing existing red tape.
The percentage of UK law that comes from the EU is difficult to calculate – not least because both the EU and the UK have laws passed by parliament as well as directives and regulations issued by ministers and officials. There is also the fact that many EU laws and directives (e.g. regarding olive trees) have little if any impact on the EU.
Depending on what you are measuring the percentage seems to be anywhere between 14% and 50%. Measuring the correct figure is is discussed in detail by Full Fact
It might be a better question to ask what EU legislation we might want to repeal in the UK, Key items that many want to repeal and think would make a considerable difference are the Renewable Energy Strategy and the Working Time Directive – on the other hand they are strongly supported by others.
“Regulation is usually intended to address market failures, such as monopoly power, externalities or to provide public goods. The potential savings from reducing regulatory costs could, however, be relatively limited once the foregone benefits of regulations are taken into account. In addition, the UK may have limited scope to change those regulations that have been largely driven by global initiatives following the UK’s exit from the EU” from PwC report commissioned by the CBI