A man who admitted assuming a false identity for 23 years has not revealed his real name, according to Kent police officers working on the case.
Police said he calls himself Christopher Edward Buckingham
Police have issued a picture of the man - who calls himself Christopher Edward Buckingham - in a bid to identify him.
Officers said he admitted making an untrue statement to obtain a passport at Canterbury Crown Court on 11 October and will be sentenced on 8 November.
The force said the man may now be in contempt for failing to give his name.
Det Con Dave Sprigg, the officer in charge of the case, said UK immigration officers checked Buckingham's passport at Calais in January when he was travelling to Kent.
They allowed him to board a ferry to Dover and arranged for him to be arrested there.
Kent Police said the man told officers he was Lord Buckingham, a title he inherited on his father's death in 1982, and showed them a letterhead bearing the Buckingham coat of arms.
But inquiries revealed that while the coat of arms did represent the Buckingham family, it had not been used since the early 1700s.
Police checks later revealed the man had taken the identity of a child born in 1962 who died nine months later.
Officers said they discovered that the man was an information technology consultant who had lived in Switzerland.
On Monday, the force said it was taking "an unusual step" in releasing the photograph.
"This man flatly refuses to reveal his identity to us and has been warned by the judge sitting at Canterbury Crown Court that he may be in contempt for failing to say who he really is," said DC Sprigg.
"If anyone recognises him, we would very much like to hear from them."