We’ve had help answering this question from our friends at UK in a Changing Europe.
The European Court of Justice’s (ECJ) powers will continue in the UK during the proposed transition period. This period will come into effect after we leave the EU next March, if a withdrawal agreement has been agreed, and is set to last until the end of 2020 (but can be extended by one or two years).
If UK laws were found by the ECJ to be going against or breaking laws laid down by the EU during the transition period, then these would have to be either interpreted in the light of those EU laws or taken off the books altogether.
This article is part of our Ask Full Fact series on Brexit, answering your questions about Brexit and the latest negotiations between the UK and the EU.