Nearly 150 Britons are among thousands of people to have bought academic qualifications from a network of fake online universities in America, a BBC investigation has found.
Fraudsters based in Spokane, Washington state, sold over $6m (the equivalent to £4m at that time) of bogus qualifications to nearly 10,000 people around the world, including medical degrees and qualifications in nuclear engineering.
The founders of St Regis University were recently sentenced to three years in prison for the fraud.
BBC Radio 5 Live's Donal MacIntyre programme tracked down two of the British people who have a PhD from the fake university.
St Regis University might have appeared to be a legitimate institution of higher education.
It had an impressive website and claimed to be accredited by the authorities in Liberia, which the founders of the fake university - or "diploma mill" - had secured by paying nearly $50,000 (more than £28,000) in bribes to officials in the West African republic.
But there were "red flags" which ought to have alerted applicants that St Regis was not what it seemed, according to assistant attorney general in Spokane, Jack Zurlini.
"There was no coursework involved. You could choose what date you graduated," he said.
"So if you had written papers back in the 80s and 90s that you felt you ought to have got a degree with, but you didn't, you could ask St Regis: 'Please backdate my degree to 1985.'"
Tom Boyd-Smith is one of nearly 150 British nationals to have acquired a fake qualification from the diploma mill.
He paid more than $1,000 (about £700) for a PhD in social sciences from St Regis University in 2003.
He submitted a thesis but admitted he had no contact with a tutor or any proper assessment.
Mr Boyd-Smith has been employed by the Royal National Institute for the Blind (RNIB) since 1996 and works as an expert witness.
He can be instructed by solicitors to calculate how much compensation claimants might be due when there has been sight loss through personal injury or medical negligence.
Mr Boyd-Smith, who has a number of legitimate academic qualifications, lists his PhD on the CV he sends out to solicitors.
But he told the BBC that he is asked to work on cases on the basis of his many years of experience as an expert witness, not his St Regis doctorate.
In a statement, he said: "While I was of course aware that the PhD was by correspondence rather than by attendance at a UK university, as my other qualifications have been obtained, I fully believed it to be valid and legitimate."
Another of the Britons who acquired a fake degree is Janet Watkinson. She is clinical director of pharmacy at Hinchingbrooke Hospital in Cambridgeshire. She paid more than $1,000 (about £700) for a PhD in pharmacology from St Regis.
She is a registered pharmacist and fully qualified for her job with the NHS. A PhD is not necessary for her current post and she did not use it to be appointed. However, she is known as Dr Watkinson at her workplace.
She was also listed as a "doctor" when she sat as a member on a local Research Ethics Committee from May 2006 to May 2008; an independent body which oversees clinical trials.
The BBC understands that in the correspondence between Janet Watkinson and St Regis University, she requested that her degree be backdated to 1985, in recognition of articles she had published in health journals.
Janet Watkinson told the programme: "I was totally unaware that the University of St Regis was not a legitimate academic body. I feel foolish to have been taken in by them.
"My objective had been to obtain recognition for research work undertaken earlier in my career."
Both Janet Watkinson and Tom Boyd-Smith say they have stopped using the title "doctor" following the BBC investigation.
Listen to the full report on BBC Radio 5 Live's investigative series presented by Donal MacIntyre on Sundays at 1900 BST or catch up on the