A judge in Amsterdam has agreed to ask the European Court of Justice preliminary questions about the consequences of Britain's departure from the European Union for citizenship rights of Britons living in Europe.

In a decision that could have consequences for some 1 million Britons living outside the U.K. in the EU, the judge said Wednesday in a written ruling that "there has to be more clarity about the consequences of Brexit for EU citizenship," according to a statement by the Amsterdam court.

British citizens who live in the Netherlands went to the court last month in a bid to retain their EU citizenship rights after Britain gets divorced from the bloc in March 2019. Lawyers for the Dutch state dismissed their case as a legal fiction.