From January 2021 the UK Courts, rather than the Court of Justice of the European Union (ECJ), will be the final arbiter of UK laws (subject to the terms of the Withdrawal Agreement and Northern Ireland Protocol).

However, as part of providing continuity and certainty to the UK’s legal system, the European Union (Withdrawal) Act 2018 (as amended) stipulates that EU or EU-derived law which the UK will maintain – referred to as ‘retained EU law’ – is, broadly, to be interpreted in line with the principles laid down by, and decisions of, the ECJ before 31 December 2020.

This continuing role for judgments of the ECJ is in turn referred to as ‘retained EU case law’. But there are reasons why the primacy afforded to such case law should not be immutable.

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