Two prison inmates have been charged with the attempted murder of drug kingpin Tony Mokbel, who remains in a critical condition in hospital.

Police on Tuesday confirmed the pair, both aged 21, had been charged with attempted murder, intentionally causing serious injury and causing serious injury intentionally in circumstances of gross violence, stemming from a stabbing at Barwon Prison yesterday.

Mokbel remains in hospital fighting for life after the incident.

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 where he remains in a critical condition.

The 53-year-old was originally considered to be in a serious but stable condition, but his condition was later upgraded to critical.

Victoria police said they were called to Barwon prison at 3.45pm and that a man in his 50s had been airlifted to hospital in a serious condition.

“A second victim, aged in his 30s, was taken to hospital by road ambulance also in a serious condition,” police said in a statement.

Mokbel was a key figure in the gangland wars in Melbourne in the 1990s and 2000s and was represented by Lawyer X, the gangland lawyer and police informant who is at the centre of an upcoming royal commission.

He was charged but not convicted of commissioning the murder of rival Lewis Moran in 2004; a crime for which Carl Williams, to which Mokbel had been linked, was later convicted. Williams was murdered in Barwon prison in 2010.

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 X scandal has opened a possible window of appeal to Mokbel.

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.