One of the most common mistakes made by A-Level students is to mix up the ECHR/ECtHR and ECJ. So what are these two institutions and why are they so different?
What is the ECtHR and the ECHR?

The ECtHR stands for the European Court of Human Rights. It is based in Strasbourg, France. It exists to adjudicate on the ECHR (European Convention of Human Rights).
In 1949, with the memory of the Second World War still heavy in the minds of Europeans, an organisation called the Council of Europe was set up. This organisation is separate from the EEC/EU. For example, until April 2022 when it was excluded after the invasion of Ukraine, Russia was a member of the Council of Europe, but is not a member of the European Union.

The aim of this organisation was to uphold human rights, democratic values and the rule of law across the continent of Europe, with the ultimate aim of preventing a Third World War from erupting on the continent.
In furtherance of this, in1950 the European Convention of Human Rights was signed. This enumerated a number of universal rights that signatories agreed to uphold. These included:
Article 2: The Right to Life
Article 3: Freedom from torture or degrading treatment
Article 6: Right to a Fair Trial
Article 8: Right to Privacy
In 1959 a European Court of Human Rights was set up to enforce these rights. Citizens of member countries could go to the ECtHR if they believed that their rights had been infringed.

For example, in Hirst v United Kingdom a convicted murderer argued in the ECHR that his Human Rights had been infringed by the UK Government when they refused to allow him to vote. The Court ruled that a blanket ban on prisoners voting did breach Human Rights.
In 1998 Britain transferred the ECHR into British Law through the Human Rights Act (1998). This means that the ECHR is now codified into British law and is adjudicated in British courts.
The ECHR does not fall under the jurisdiction of the European Union in any way. However, perhaps confusingly, one of the conditions required for joining the EU is that they accept the European Convention of Human Rights.
What is the ECJ?

The ECJ is the European Court of Justice. This is the court that is responsible for interpreting and ensuring the implementation of EU law across the 27 countries that now make up the European Union.
The court is made up of 27 judges, one from each member country. Normally, cases will only be heard by a maximum of 15 judges.
Leaving the jurisdiction of the ECJ was a key argument of the Leave campaign during the Brexit Referendum and was a key component in trying to reach a withdrawal agreement between 2016 and 2020. As of 2022 Britain is no longer bound by any rulings of the ECJ.
Article Summary
Although often confused, the ECHR/ECtHR and the ECJ are often confused with each other. One is a continental mechanism for enforcing human rights whilst the second is the judicial arm of the European Union. This means that some countries outside of the EU are members are signatories the ECHR, but are not bound by the ECJ. As of 2022 Britain is one of those states.
Key Terms
European Convention of Human Rights – An international treaty to protect and enforce fundamental Human Rights in Europe. It was signed in 1950. In 1998 it was codified into UK Law in the Human Rights Act.
European Court of Human Rights – The Court based in Strasbourg that considers human rights cases under the ECHR.
European Court of Justice (ECJ) – The court of the European Union in Luxembourg. It is responsible for overseeing cases whereby Member States have questioned, or have not followed, European Union directives and regulations.
Hirst vs United Kingdom – A ECtHR case in which a British prisoner called John Hirst argued that denying prisoners the vote was a denial of their fundamental human rights. The court partially ruled in favour of Hirst saying that a blanket ban on prisoner voting was an infringement of their rights under the ECHR.
Council of Europe – An organisation founded in 1949 which oversees rights in Europe. Its members sign the ECHR and agree to the adjudication of cases at the ECtHR.