How are Britain and Ireland benefiting from EU membership?

As of my last knowledge update in October 2023, Britain has officially left the EU, but prior to Brexit, both Britain and Ireland benefited from EU membership through access to the single market, which facilitated trade and economic growth. Ireland, being an EU member, gained significant financial support and investment opportunities, particularly through agricultural subsidies and regional development funds. Additionally, both countries enjoyed enhanced cooperation on issues like security, environmental policies, and migration, fostering closer ties and stability in the region.