The Court of Justice of the European Union (CJEU) (including the General Court) comprises judges nominated by each of the European Union (EU) Member States.
A judge does not represent the interests of the Member State which nominated him or her. Equally, judges do not have to participate in cases involving their own Member State.
Along with the judges of the CJEU, some EU Member States also have the ability to nominate an Advocate General in the CJEU (but not in the General Court). An Advocate General is a person having the same status as a judge of the CJEU who gives his or her opinion on how a case should be decided but the CJEU is not bound to accept the opinion of the Advocate General. There were 11 Advocates General with six of them nominated every time by France, Germany, Italy, Poland, Spain and the UK with the other five nominated by the other Member States in rotation.
On 31 January 2020, the UK left the EU. One would therefore expect that the Judges and the Advocate General nominated by the UK would also have left the CJEU. However, EU-UK withdrawal agreement provides that many of the EU rules continue to apply to the UK during the "transition period" until 31 December 2020. The CJEU continues to have jurisdiction in any proceedings brought by or against the UK before the end of the transition period, which is set as 31 December 2020. It is also to continue to have jurisdiction to give preliminary rulings on requests from courts and tribunals of the UK made before the end of the transition period.
So, what happened with the Judges and Advocates General? Did they stay or did they go?
The mandates of the Judges and the Advocate General nominated by the UK ended on 31 January 2020.
The three judges nominated by the UK in the CJEU left with immediate effect.
The position of the Advocate General nominated by the UK (namely, Eleanor Sharpston) is somewhat different.
Because of a declaration by the Member States on 29 January 2020, the number of Advocates General, is not affected by the UK's withdrawal.
So pending the nomination of a new Advocate General by the governments of the Member States, Eleanor Sharpston will continue to hold office. She holds office in accordance with Articles 5 and 8 of the Statute of the Court of Justice. She will hold office until her successor takes up his or her duties.
Three Judges left but the Advocate General remains in place. In some ways, this is symptomatic of the way in which the UK still has one foot in, and one foot out of, the EU.