As it stands the UK implements an EU law which prevents the reverse engineering of proprietary software with few exceptions, could this change once we leave the EU?
There are two kinds of EU laws: regulations and directives.
- Regulations have direct effect throughout the EU, which helps harmonize the laws of the Single Market.
- Directives instruct the member states to implement their own laws to some effect, which helps adapt the laws to that member state's circumstances.
Reverse engineering is the subject of the EU Computer Programs Directive. As a directive it has no direct effect in the UK. The directive was implemented by amending the UK's Copyright, Designs and Patents Act 1988.
The Copyright Act is UK law, created by parliament and not the EU. It will continue to be in effect even after a Brexit.
Note that many EU regulations also have corresponding passages in UK law, for example the Data Protection Act 2018 mirrors the GDPR. And per the European Union (Withdrawal) Act 2018, all relevant EU laws will be transformed into domestic UK law upon exit day, including the principle of supremacy of (ex-)EU law over domestic law. That way, the regulatory environment doesn't suddenly change. So even if reverse engineering were the subject of an EU regulation, it would continue to apply after Brexit and would supersede pre-Brexit UK laws to the contrary.
As you correctly formulated:
UK implements an EU law
which essentially means: It is a directive of the EU.
There are (at least) two kinds of EU laws to be distinguished:
- directives have to be implemented, that is written into national law. Member states have to pass these laws.
- regulations take effect immediately, without needing to be passed as national law.
The law about reverse engineering is a directive. So, it is a UK-implemented law, valid in the UK, independend from remaining in the EU.
The UK has implemented EU directives, and EU regulations are automatically law in the UK. There are preparations so that all the EU regulations, which will cease to be law in the UK the moment the UK leaves the EU, will all be replaced by equivalent UK laws at the same moment.
So apart from possibly mistakes in that process, and slightly changed wording in some of the replacement laws for EU regulations, the laws in the UK one second after Brexit will be the same as one second before Brexit.
After Brexit, the UK is obviously free to change any UK laws. If they want to change the laws about reverse engineering of proprietary software, then they can and probably will. If they don't want to change those laws, they won't. I haven't heard any big complaints from politicians about these laws, so they might stay unchanged for quite a while.