A group of UK citizens who live in the Netherlands have gone to a Dutch court in a bid to retain their EU citizenship rights post-Brexit.

In a case that could have far-reaching consequences for around one million Britons currently living in European Union countries outside the UK, lawyer Christiaan Alberdingk Thijm launched summary proceedings on Wednesday before a judge at Amsterdam District Court.

Mr Alberdingk Thijm said he wants the Amsterdam judge to put so-called “prejudicial questions” about the status of UK nationals post-Brexit to the European Court of Justice.

The lawyer added that while citizens’ rights are clear when a country joins the EU, nobody knows what happens when a country decides to leave, as the UK has done.

According to the Treaty on the Functioning of the EU, any person who is a citizen of an EU nation automatically is also an EU citizen. EU citizenship grants rights, including the freedom to move and live freely within the bloc.

Brexit negotiators have made progress on the protection of rights of EU citizens living in Britain and UK citizens living on the continent, but no full agreement has been reached yet on the issue and lawyers for the plaintiffs said the progress so far has left their fate up in the air.

British lawyer Jolyon Maugham, who is funding the case, said that if the Dutch judge puts questions to the Luxembourg court, “the answer the Court of Justice gives will be an answer that applies to UK passport holders wherever they live”.

Mr Maugham said before the hearing: “I am profoundly concerned about what the loss of EU citizenship means for the million or so UK citizens who live and work in the EU.

“I am also profoundly concerned for the 64-odd million people living in the United Kingdom who, but for this litigation, will lose the ability to exercise EU citizenship rights in the future.”

Mr Alberdingk Thijm told the Dutch judge: “Your honour, the fate of British citizens living in the Netherlands is in your hands.”

However, urging the judge to reject the request, lawyer Georges Dictus, representing the Dutch state and the Amsterdam municipality, said that once Brexit is finalised, EU treaties will no longer apply to British citizens and that any rights must be laid out in an agreement between the UK and the EU.

Another lawyer representing the Dutch state, Erik Pijnacker Hordijk, called the case “fictional, artificial”, and said the plaintiffs were attempting to use the Amsterdam court as a stepping stone to get to the EU court in Luxembourg.

He urged the judge to reject their request, saying it could potentially delay Brexit negotiations as a ruling from Luxembourg would likely take many months.

The lawyer added that the Britons were taking their case to the wrong court, saying: “If British citizens believe they have a legal right to a particular treatment post-Brexit, they should direct themselves to their own government or a British judge.”

A ruling is expected in three weeks’ time.