Even people who have been in the UK since before it joined the EU are not exempt from the settlement scheme.
Former public servant Elly Wright, 77, moved to England from the Netherlands in 1967.
Due to Dutch law she was unable to take British citizenship without giving up her original passport.
She told the Press Association: “It seems a ridiculous situation if you are in the tax system and have paid tax for many years and you are an European citizen, you now have to ask to stay in your own home and pay for that privilege.”
I was fully integrated and I had done all my study here - it was such a slap in the face to realise that you were now 'the other' Elly Wright
Mrs Wright’s late husband was British, while her son from a previous marriage also only has British citizenship.
She added: “I never applied for British citizenship because it just wasn’t necessary – we were all Europeans in the end.”
Mrs Wright, who lives in Epsom, Surrey, spent years working for the NHS after starting out as a medical secretary.
She later moved into social housing as a welfare officer and later as an allocations officer with the Notting Hill Housing Trust. She is now a painter.
“I always felt like one of the Brits, I never felt different,” she said.
“I was fully integrated and I had done all my study here – it was such a slap in the face to realise that you were now ‘the other’.”
Mrs Wright said many people in her situation were concerned about giving the Home Office permission to share their personal data with other agencies in the UK and abroad while they cannot access the data the Home Office holds on them.
She also voiced her frustration at the fact the Home Office’s settlement scheme app does not work on iPhone and iPads – the devices she owns.
“You can ask someone to borrow their device but that alone is going to take more than half an hour,” Mrs Wright said.
From her involvement with groups set up to advise EU nationals living in the UK during the Brexit process, Mrs Wright has met many older people with limited computer skills who she said were very concerned about the application.
She said: “Some of them don’t even have a mobile phone and there are people who live in care homes, what are they supposed to do?”
She added: “The entire application process is in digital format and if successful, applicants are not given a printed card or letter confirming their settled status.
“The absence of written proof is another worrying aspect.”