The revelation sheds new light on the close relationship between the Turnbull family and the former ABC chairman - who was in business with Malcolm Turnbull at Ozemail in the late 1990s. Senior ABC sources said there was no connection between the audio leak investigation and demands Mr Milne made to former managing director Michelle Guthrie to sack Alberici and political editor Andrew Probyn. They suggested the broadcaster would have investigated the leak regardless. But the swift action taken against Lloyd - who was suspended in early September - and the slow investigation have irked journalists and the union, as well as some members of the ABC board. Alex Turnbull confirmed he called Mr Milne and threatened to lodge a formal complaint if the leak was not investigated. "I wanted it dealt with but I didn’t want to start World War III," he told Fairfax Media. "I pointed out the nature of how these records are stored and how easy it is to check who accessed them."

Mr Turnbull said the person responsible was obviously "not too bright, and technically illiterate". Mr Milne declined to comment and Ms Guthrie could not be reached on Wednesday. Loading Replay Replay video Play video Play video The Australian Financial Review reported that the leaked audio showed Mr Turnbull "stumbled" and was "uncharacteristically cautious" when Alberici asked if he was accusing mining magnate Gina Rinehart of exercising undue influence within the Liberal Party. That was "up for people ... to look it up", Mr Turnbull reportedly said, before expressing fears of a defamation lawsuit.

Loading Mr Turnbull also contacted Alberici following the leak, who assured him action had been taken. When contacted by Fairfax Media, Alberici said the topic was "bullshit", asked "why don't you guys do some real news?" and hung up. While the incident was first investigated by the broadcaster's human resources division, the ABC has now tasked in-house counsel Loch van den Berg with completing the probe. Lloyd denies leaking the audio, but admits sending it to his personal email address. He says he did so in order to access the file from home. The long-serving journalist is a controversial figure inside the ABC. In 2008 he was arrested on drugs charges in Singapore and jailed for 10 months for possessing methamphetamine or "ice".

The ABC has been shaken by the unprecedented events of the past six weeks, in which Ms Guthrie was sacked by the board, and Mr Milne quit days later after Fairfax Media revealed allegations he tried to interfere in staffing and editorial matters on behalf of the Coalition government. The broadcaster is now responsible for three significant inquiries: an external probe by barrister Jonathan Forbes into Ms Guthrie's claims about Mr Milne, an internal investigation into whether NSW Opposition Leader Luke Foley sexually harassed an ABC journalist and the Lloyd matter. Former prime minister Malcolm Turnbull with son Alex. Credit:AAP Internally, Lloyd's suspension has exposed deep tensions among senior program makers at the ABC. Lloyd has written to staff-elected board director Jane Connors accusing news director Gaven Morris and head of radio current affairs, Tanya Nolan, of improperly telling colleagues he was suspended. "I want their heads," he wrote. "They have lost any claims to authority in carrying out solemn duties in a publicly-funded organisation."