When news of the Melbourne gangland High Court case hit the news last week, someone, on deep background, commented that it would be like a bomb going off. "A nuclear bomb," they added.

They weren’t wrong. The case, which has been wending its way through the court system for years, has revealed that for four years, from 2005 to 2009, a leading Melbourne criminal barrister representing a slew of Melbourne gangland figures, was also acting as a police informant.