Tony Mokbel – one of the key figures in Melbourne’s years-long gangland war – was handed a 30-year prison sentence in 2012 after pleading guilty to masterminding an elaborate drug syndicate.

Violence linked to his group, known as “The Company”, claimed dozens of lives and was later immortalised in the hugely popular Australian TV series Underbelly.

But it was later revealed that Mokbel’s high-profile lawyer at the time, Nicola Gobbo, was feeding information to police while supposedly defending her clients.

Mokbel spent about 18 years behind bars but was released on bail this year after a court ruled he had a strong chance of overturning the criminal convictions.

His appeal hinged on the fact that he would not have pleaded guilty if he had been aware of Gobbo’s double life, his legal team told Victoria’s Court of Appeal this year.