Currently, expats who have not been resident in the UK for over 15 years are ineligible to vote in general elections. Despite hope that the restriction would be ditched for the referendum, it remains in place, much to the anger of long-term expats.

READ: Ten-point guide on how to register to vote in the EU referendum

This group is estimated to number 2.2 million – almost half of the 5 million Britons currently living abroad. There is no exact figure on the number of Brits living in Spain who will be unable to vote, but  of the 283,000 Britons registered on the padrón as resident in Spain, just 11,000 are registered to vote in the UK.

Lawyers will lodge the claim at Britain's High Court on Wednesday, acting on behalf of a group of expats, which was started by 94-year-old war veteran Harry Shindler, who lives in Italy and has previously petitioned the European Court of Human Rights (ECHR) about the law.

The group argues that the EU Referendum Act, which gives votes to groups who are not normally permitted to vote in UK general elections including Irish and Commonwealth citizens living resident in Gibraltar, but excludes long-term expats in Europe, is a breach of their rights.

“Our clients are being penalized for exercising their EU free movement rights,” said lawyer Richard Stein from firm Leigh Day. “The people it arbitrarily excludes are those UK citizens who are among those most likely to be affected by the decision taken by voters in this referendum.”

“Not to allow them to vote on the decision whether the UK remains part of the EU is unlawful and we have asked the court to deal with the issues urgently so that the act can be amended before the June date, to include all UK citizens residing in the EU for however long.”

The case if successful could have a huge impact on preparations for Britain’s EU referendum on June 23rd.

At the last general election in 2015, 106,000 Brits who had been resident abroad for less than 15 years registered to vote.

While expatriates who have lived abroad long-term may not be significantly affected by the results of general or local UK elections, the Brexit referendum would have a huge impact on their lives.

At the last UK general election, David Cameron’s Conservative Party pledged to “introduce votes for life, scrapping the rule that bars British citizens who have lived abroad for more than 15 years from voting”. However, this change will not come into force before the referendum.

Lennox Napier, a campaigner living in Mojacar, southern Spain argues that Britons living in Europe for longer than 15 years “have no voice, no champion, no representation”.

“If London left Europe, then the Britons living in France, in Spain, in Germany or in Poland would find their lives changed considerably, but worst of all, no one knows by how much. It would not even be a decision made by the British as to what would happen to us, after all, they would no longer be a part of the European Parliament,” he told The Local.

“In Spain, we would expect to be treated as non-European citizens with the return of work permits. We would have convertible accounts at the bank and a visa in our passport. We would lose medical coverage and social security. We would of course lose the vote locally (many of us have already lost it in the UK) leaving us even more 'voiceless and forgotten',” he said.

If the legal bid proves successful, the referendum scheduled for late June may have to be delayed while the extra names are added to the electoral register.

If you are a British expat and have been living in Spain for less than 15 years, you can vote in the EU referendum on June 23rd. To register CLICK HERE.

Tell us what you think at The Local Spain Facebook page or send an email to [email protected]