The Brits went to court in Amsterdam in January to ask that their case be referred to the ECJ on the grounds that their existing rights could not be removed once the UK leaves the EU, reports newspaper the Guardian.
The judge agreed and is expected to issue two draft questions to be put before the ECJ within the next two weeks.
The first question asks the ECJ panel of judges to determine whether Brexit means British nationals will automatically lose their EU citizenship and all the rights that flow from that, including freedom of movement, the newspaper reported.
If the answer to that question is no, then the ECJ judges are asked to determine what, if any, conditions or limitations should apply to the maintenance of those rights once Britain leaves the EU.
It should be noted, however, that a victory for British expats in Europe would not be reciprocated for EU expats in the UK.
The UK Government has already stated that it will only guarantee rights for people who have been continuously and lawfully living in the UK for five years by 29 March 2019. This means they will be free to live in the UK, have access to public funds and services and can apply for British citizenship.
Those not meeting the five-year criteria will be able to apply for settled status/indefinite leave to remain – it will not be guaranteed.
The case is being funded and supported by QC Jolyon Maugham, who has raised a series of legal challenges against Brexit.
He said that the outcome of the case would be “profoundly important” for British people living in the EU, adding that he was heartened by the attitude of the Dutch court.
“The UK courts seem to find themselves cowed by the political dynamic,” Maugham said. “I’m very pleased that judges elsewhere are able to separate out political and legal considerations.”
He later tweeted: “If this case succeeds, it would give EU citizenship rights to 60 million people – even after Brexit. The most important piece of litigation of modern times?”