LONDON (Reuters) - Millions of EU citizens living in Britain can register from Monday for settled status after Brexit but a research group warned that many could still be left out in the cold and some EU nationals are attending support groups to cope with the stress.

FILE PHOTO: An anti-Brexit protester walks outside the Houses of Parliament in London, Britain January 17, 2019. REUTERS/Clodagh Kilcoyne/File Photo

Britain is home to about 3.5 million EU nationals and many of those will need to apply for inclusion on a new “settled status” register before July 2021 if they want to stay. Britain is due to leave the European Union on March 29 this year.

Britain’s interior ministry on Monday began the first public testing of the registration system for all EU citizens who hold a valid passport and any non-EU citizen family members who hold a valid biometric residence card.

“From the very beginning we have been clear that securing the rights of EU citizens living in the UK is our priority,” immigration minister Caroline Nokes said, adding that the new settlement scheme would be “easy and straightforward” to use.

Prime Minister Theresa May later told parliament Britain would waive the 65 pound ($84) application fee for EU nationals wishing to stay and would reimburse anyone who has already paid.

A private phase of testing of EU citizens working for health service trusts and universities in the north-west of England between November and December involved almost 30,000 applications and none were rejected.

However, research group British Future said the scheme could harm vulnerable groups such as the elderly and people with limited English or computer skills, and warned of a new Windrush scandal unless the government addressed its shortcomings.

Britain apologized last year for its “appalling” treatment of thousands of Caribbean migrants - the “Windrush generation” - who were denied basic rights after a tightening of immigration policy, despite having lived in the country for decades. Some were wrongly deported.

After Brexit, some EU nationals could be left “destitute, barred from working, at risk of exploitation and unable to access basic services” under the new scheme, the British Future report said.

With just over two months left until Brexit, there is still no agreement in London on how and even whether it should leave the world’s biggest trading bloc.

BREXIT ANXIETY

In a sign of the anxiety felt even by some longtime EU citizens living in the UK, the Swedish Church in London hosted a discussion last week of problems they face because of Brexit.

Freelance writer and German national Anette Pollner who has lived in Britain for almost 30 years but does not have a British passport, said she was terrified that her settled status application would be rejected because she may not have the correct documents to prove her right to remain.

Pollner said she had experienced increased hostility towards her since Britain voted by 52 percent to 48 percent in June 2016 to leave the EU after more than four decades.

“Since the referendum we have been living in a state of constant fear,” she said.

“I am taught a lesson every single day that I am not welcome here in so many different ways. When people hear my foreign accent it’s a kind of racism, they respond to me just like they respond to someone who has a different skin color.”

British psychotherapist Susie Orbach said EU citizens living here had faced much greater uncertainty over their rights since the referendum, and some felt Britons no longer wanted them around.

“The issue of Brexit has hit my consulting room from the day after the vote, where there was absolute shock and confusion,” she told the event.

“For some people who may have even been brought up here in England but have not ever turned themselves into citizens it’s been very confusing and quite scary.”

($1 = 0.7772 pounds)