Decorated veteran Ben Roberts-Smith’s latest battle to clear his name hinges on a secretly recorded call involving an award-winning journalist.

A “recording made in secret” has been ruled admissible in Roberts-Smith’s bid to reopen his appeal for his unsuccessful defamation case against Nine newspapers.

The ruling comes despite Nine’s lawyers arguing the audio should be treated with “great caution”.

Nick McKenzie wrote a series of reports for Nine newspapers in 2018 describing the former soldier as a war criminal, an allegation a judge later found was true on the balance of probabilities.

Roberts-Smith is pushing to reopen his appeal against the judge’s finding, which he said involved a miscarriage of justice because McKenzie unlawfully obtained details about the former soldier’s legal strategy.

In a taped call, the journalist tells Roberts-Smith’s ex-lover that the soldier’s ex-wife and her friend had been “actively briefing us on his legal strategy”.

“I shouldn’t tell you,” the journalist said.

“I’ve just breached my f***ing ethics in doing that, like this has put me in a s**t position now.”

The towering Roberts-Smith faced the Federal Court on Thursday alongside his parents, who have previously called McKenzie’s phone call “concerning”.

But a lawyer representing Nine and McKenzie earlier argued the call should not be admitted to evidence because the person who sent the recording to Roberts-Smith’s lawyers may have broken the law.

The sender was aiming to inflict “maximum harm” on his clients when they sent the email titled “Secret McKenzie recording” with the 85-second audio file, Robert Yezerski SC said.

The audio had been captured without McKenzie’s knowledge and only showed a portion of a much longer conversation, the Nine lawyer noted. 

“We know at least the beginning and end of the conversation has been excised from the recording,” he said. 

“There is real reason to treat (the recording) with great caution.”

The Victoria Cross recipient claims his ex-wife, Emma Roberts, accessed his email accounts and leaked sensitive information to McKenzie, who used it to shape his approach to the defamation suit.

The former soldier’s lawyer argued the recording contained a serious admission by McKenzie and should be admitted to evidence.

There was no evidence about who had sent the email, which came from an encrypted account, the court was told.

McKenzie’s lawyers say the phone call recording should be treated with caution. Photo: AAP

The secret call came to light after the ex-elite soldier’s 10-day appeal was heard in early 2024 but should be considered before the judges deliver their decision, his lawyers maintain. 

If his appeal is unsuccessful, only the High Court could overturn the war criminal finding.

Roberts-Smith rose to prominence in 2011 after he was awarded Australia’s highest military honour, the Victoria Cross, for single-handedly taking out machine-gun posts to protect pinned-down colleagues in Afghanistan.

His reputation, however, was tarnished in 2018 after McKenzie’s explosive reports alleging the special forces veteran was complicit in the murder of four unarmed men during his deployment in Afghanistan.

In June 2023, Justice Anthony Besanko found the reports had been proven on the balance of probabilities – a lower standard than in a criminal proceeding.