All is not quite as it may seem, 3Ts.
The court on this occasion was considering the case of a single appellant – a French murderer – who had been denied the right to vote in EU elections. He argued that the EU Charter on Fundamental Rights afforded him the right to vote and that right was being taken away. The ruling said that in his case the ban was justified and proportionate, bearing in mind the nature and gravity of his offence.
The ECJ ruled the EU Charter applies to the right of UK citizens, including prisoners, to vote in European Parliament elections. Any deprivation of that right by a state has to be proportionate and justified, and must take into account the nature and gravity of the criminal offence committed and the duration of the penalty.
In France only prisoners sentenced to five years or more are denied the vote. The UK has a blanket ban, no matter what the offence or the sentence and it is this that is being challenged. This means that it is open to prisoners in the UK who are EU citizens, especially those serving shorter sentences for less serious crimes to challenge the ban on them voting in elections to the European Parliament. This issue has still to be ruled on.