EU nationals living in the U.K. take part in a demonstration at Parliament Square on November 05, 2018 in London | Dan Kitwood/Getty Images EU citizens tackle UK elections watchdog over ‘voter suppression’ Citizens’ rights group claims up to 2 million people could be disenfranchised.

LONDON — EU27 citizens in Britain registered an official complaint Tuesday about what they called widespread "disenfranchisement" in the upcoming European Parliament election, amid claims that up to 2 million people could be left without a vote on Thursday.

A group representing European Union nationals living in the U.K., called "the3million," has written to the Electoral Commission to complain about its handling of the election.

To vote, EU citizens from outside the U.K. have to fill in a government form guaranteeing they will not vote in their home country as well.

However, MPs and campaigners say millions of citizens are not aware of the bureaucratic hoop and may turn up at polling stations Thursday only to be turned away.

The Change UK MP Mike Gapes has campaigned in parliament for EU citizens to be able to fill in the form at polling stations to get around the problem.

Gapes told POLITICO he thinks the government is refusing to listen because it wants fewer EU citizens to vote.

“The government are not budging at all," he said. "The Electoral Commission have written to me to say it’s not their fault. Potentially, 2 million EU nationals are being disenfranchised as a result. There was no real effort by the government. It’s a voter suppression exercise by the Conservative government because they don’t want EU nationals to be able to vote.”

EU citizens in the U.K. have now taken their complaint to the Electoral Commission — the official elections watchdog — while continuing to push for the UC1 form to be made available at polling stations.

“To mitigate the damage done to the democratic process in the UK the3million is campaigning for EU citizens to be able to sign this little-publicised form on the day of vote,” a statement released Tuesday states.

The group cites numerous examples of EU citizens trying but failing to fill out the form.

“One Dutch couple, having lived in Prime Minister Theresa May’s constituency in Maidenhead for the past 26 years, was told the EC6 form had not been received, despite the couple posting it on 23 April, two weeks before the deadline,” a statement from the group says.

In a statement, the couple told the3million: “It is a basic human right to vote, having had no say in Brexit this vote was extremely important to us.”

In another example, the3million says one EU citizen was told — contrary to U.K. electoral law — that she had to be British to vote, the group said. It also claimed letters of refusal have been sent to EU citizens who had been told over the phone that the form had been received and that they were set to vote.