The director of public prosecutions has admitted an error was made by the Crown Prosecution Service (CPS) during a Mafia boss's extradition proceedings.
Alison Saunders said the administrative error "shouldn't have happened".
Domenico Rancadore, 65, was freed on unconditional bail after the CPS failed to lodge legal papers within the time limit.
Mr Rancadore was arrested in August after evading the Italian authorities for 20 years.
He won an extradition battle after a judge ruled prison conditions in Italy would breach his human rights.
Following the ruling the CPS had seven days to lodge an appeal at the High Court and to serve papers to Mr Rancadore's lawyers.
It failed to serve the papers to his lawyers on time.
Ms Saunders acknowledged that as a result of the error it was possible Mr Rancadore may never be extradited to Italy.
She said: "We are obviously looking very closely into why it happened and making sure that it doesn't happen again."
She said officials were talking to the Italian authorities about what could be done to "make this right".
Mr Rancadore moved to London from his native Sicily in 1994 with his wife and two children.
He was found guilty of Mafia association and extortion in Italy in 1999 and given a seven-year jail term in his absence.