The Home Office has apologised after a man who has lived in Britain all his life was told he must leave the country or face the possibility of jail.
Shane Ridge, 21, received a letter from the Home Office's immigration and enforcement department telling him that he had "no lawful basis" to be in the UK according to their records.
Mr Ridge, said to be a joiner from Colne in Lancashire who described himself "as British as they come", was shocked and confused after receiving the letter, the Guardian reported.
The letter, which warns Mr Ridge he is at risk of losing his driving licence, advises him to "take steps to leave the UK immediately" or face possible prosecution, a fine of up to £5,000 and six months imprisonment.
An error made by the Home Office meant that officials failed to establish his maternal grandmother was British when Mr Ridge applied for the right of abode in the UK.
The department has since reviewed his application and concluded his British citizenship should have been established in March 2017.
A Home Office 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."
A week ago the Home Office was forced to apologise after around 100 letters were wrongly sent to EU nationals warning them they face detention and removal from the UK.
An urgent investigation was launched into the error, which emerged after a Finnish academic posted about correspondence she received from the department on social media.
Eva Johanna Holmberg, who is married to a Briton, was told she had a month to leave. She was also warned that she was "liable to be detained".
The Home Office said last week that it was telling recipients of the "limited" number of letters to disregard them, adding that the rights of EU nationals in the UK "remain unchanged".