Bridgitte Tetteh
BBC Radio Berkshire
A local councillor who was told he would have to pay for his NHS care has described the error as "dehumanising".
Biyi Oloko compared the mistake by staff at the Royal Berkshire Hospital (RBH) in Reading to being "strip-searched" despite doing nothing wrong.
Mr Oloko moved to the UK in 1979, is a British citizen and an elected member of West Berkshire Council - but believes his name and accent led to incorrect assumptions.
RBH apologised and said it was "looking into the way this matter was handled".
The hospital had rearranged an MRI scan appointment for Mr Oloko from February to this Friday.
However, he said he had a trip abroad planned for Sunday and contacted the hospital to rearrange before changing his mind.
Instead, he decided to ask his GP to check he would be fit to fly so soon after the scan.
"Then an email comes through and the email says that I need to complete this questionnaire [to prove my nationality]," he said.
At the bottom of the email chain it said his attempts to change the appointment date "sounded suspicious".
"I think in their mind as soon as they heard... the accent, the name, 'out of the country'... they just put everything together incorrectly," he said.
Mr Oloko told RBH he was a British citizen and an elected councillor, but said they responded by saying they were researching whether a person had to be a UK resident to be a councillor.
In his most recent letter from the hospital, Mr Oloko was told his care was chargeable and he could "experience a delay for non-urgent treatment" until it was paid.
He said it was "dehumanising" to be asked to prove he is entitled to free NHS care.
"Free treatment is my right in this country because I'm a citizen, I have worked and I've paid taxes in this country for over 30 years," he said.
"No one can deprive me of that right."
A spokesperson for RBH said: "We apologise for any distress to Councillor Oloko and are looking into the way this matter was handled."