The Home Office has apologised for telling a man who has lived in Britain his entire life that he must leave the country or face the prospect of jail.
Shane Ridge, 21, of Colne in Lancashire, received a letter informing him he had "no lawful basis to be in the UK" according to the government department's records.
Mr Ridge was left mystified because all of his relatives are British citizens.
The Home Office said it had now apologised to him for its mistake.
'Leave UK immediately'
The problem arose because of confusion about the status of Mr Ridge's mother, who was born in Australia while the family was living there for a short time.
Home Office officials had failed to establish that his maternal grandmother was British, and his mother had dual nationality.
Mr Ridge said the letter, received on 17 August, appeared to have been prompted after he passed a UK driving test earlier this year.
It warned Mr Ridge he was at risk of losing his driving licence and advised him to "take steps to leave the UK immediately" or face possible prosecution, a fine of up to £5,000 and six months imprisonment.
Mr Ridge, who works as a welder, said it was a further blow because he had previously had an application for a British passport rejected.
'Automatically a British citizen'
Instead, he was confusingly urged to apply for "right of abode", a status that would give him the right to live in the UK and travel in and out of its borders.
"It's been a week of hell," Mr Ridge said.
"They've said they will sort things out and I can get a British passport, but they haven't given me a lot of information and I still feel in the dark about what's happened.
"I've lived here all my life and pay tax and national insurance. It's ridiculous."
The Home Office has since reviewed its records and a spokeswoman said: "We have now established that Mr Ridge is automatically a British citizen.
"We have spoken with Mr Ridge to apologise for this error and the distress caused.
"When Mr Ridge applied for right of abode, we did not identify that his maternal grandmother was British and that as a result his mother had settled status in the UK at the time of his birth."
