Both the EU and the UK have been leaders in the Open Access shift for some time. In April the EU, currently led by the Netherlands, published a very ambitious plan (the Amsterdam Call to Action for Open Science) to shift all scientific publications to OA by 2020 and to make all publicly funded research data openly available.
Two blog posts look at the possible effects on OA progress of the budget pressures and the structural changes the Brexit will cause:
Open Access and Brexit
Brexit: Risks to the Knowledge Economy and the Money Scrum