The best free site for case law of the United Kingdom and Ireland is probably the British and Irish Legal Information Institute – http://www.bailii.org/

It contains case law from across the UK, for all levels of court, including specialised areas for the Court of Protection (Mental Capacity Act cases) and the First-tier Tribunal (Health Education and Social Care Chamber), which includes Mental Health Act tribunal decisions, and a full range of Law Commission since 1965.

Case law from the European Court of Human Rights can be found at https://www.echr.coe.int/Pages/home.aspx?p=home [click on the case law tab for an extensive database of cases]