The European Court of Human Rights has nothing to do with the EU. It’s an entirely separate institution, with separate membership, set up by Britain after World War II to enforce the Convention on Human Rights which we helped to write. Britain has always been a signatory to this convention, and leaving the EU wouldn’t change that. Evidence
Incidentally, despite the widespread myth that the European Court of Human Rights and the UK are forever at loggerheads, figures show that the Court rules against the UK in less than 1% of all the cases we’re involved in! Evidence