I’m a Brexiteer and glad that the UK has left the EU too, but regardless of UK no longer being a member of the EU, what happens in EU member states with regards human rights and freedoms as well as across the world can make a ‘difference’ here. You see, I think all power-hungry governments, including the UK government see what other nations get away with in terms of abusing human rights and have the mind to copy it, if other countries get away with it.
The UK is still a signatory to the European Convention on Human Rights. (Strangely the EU is not a member of the ECHR)