The European convention on human rights is not an EU thing, so brexit doesn’t mean dumping it automatically.
Our government does want out of echr because it says we have a right to privacy of communications, meaning blanket surveillance is illegal, and it says torture is bad, so we can’t send nasty people back home if home is a nasty state that might torture them
Never spoke of the ECHR. In fact there are several other treaties, many of them related to the EU, protecting human/civil rights of citizens of EU member states. The Charter of Fundamental Rights of the European Union is one example (guess who got an opt-out).