Drug kingpin Tony Mokbel is in a critical condition after bring viciously stabbed at the same Victorian prison where fellow gangland identity Carl Williams was killed.
Aerial footage from Barwon Prison on Monday showed Mokbel bare-chested as paramedics rushed to his aid after reports the 53-year-old was stabbed in an exercise yard.
He was taken to Royal Melbourne Hospital by helicopter while a 31-year-old inmate was transported by road ambulance to hospital in a serious condition.
No prison staff were injured.
The 53-year-old was originally considered to be in a serious but stable condition, but Royal Melbourne Hospital later upgraded his condition to critical.
Mokbel hit headlines in recent weeks after news broke that his former lawyer had acted as a police informer, dishing dirt to detectives to help secure convictions.
After fleeing Australia while on trial in 2006, Mokbel was captured in Greece in 2007 and was sentenced to a 30-year jail term for drug crimes, with a minimum of at least 22 years before being eligible for parole.
But the lawyer informant scandal has opened a possible window of appeal to Mokbel.
The stabbing comes a day after News Corp ran an article "Tony the enforcer" about Mokbel's rise as a "feared prison big-wig".
The Herald Sun reported that Mokbel intervened to stop an extortion attempt of a 19-year-old prisoner in jail for the first time.
"When the Islanders were spoken to, on (Mokbel's) orders, the scared young prisoner was left alone immediately," the newspaper reported.
Williams was bashed to death at Barwon in April 2010 by fellow inmate Matthew Charles Johnson.
Williams' killing came on the same day as a newspaper report outlining that taxpayers paid for the multiple murderer, drug dealer and underworld figure's child to attend an exclusive private school through a deal with police.
Investigations into Mokbel's stabbing are continuing, police say.