South Australia’s highest court has ruled millions of messages sent and received across the encrypted AN0M application were lawfully obtained.

In a major legal milestone for the Operation Ironside cases around the country, three justices of the Court of Appeal handed down the decision for a test case involving two accused in front of a courtroom packed with legal identities and detectives.

“The court has determined that the use of the AN0M application platform did not involve interception,” President of the Court of Appeal Justice Mark Livesey said.

“The challenges to the validity of the authorisations referred to as ‘major control operations’ have not been made out and that otherwise the challenges have been rejected.”

The encrypted application AN0M was at the centre of the three-year global collaboration between the Australian Federal Police (AFP) and the Federal Bureau of Investigation (FBI), which used the encrypted messaging service to lure alleged criminals into revealing their secrets to police.

The AFP led the operation and sifted through around 19 million messages received through AN0M.

Police deliberately placed the encrypted messaging app in the hands of alleged criminals in 2018.

The app was at the centre of a joint operation between the AFP and FBI.(Supplied: FBI)

It is alleged black-market phones installed with the so-called Trojan horse app were being passed around the underworld from that time in the belief they were off the police radar.

When the AN0M app was disabled on June 7, 2021, authorities around the world arrested hundreds of alleged users of the devices.

In Australia, more than 250 people have been charged after raids connected with the operation.

Those accused of using the app have been charged with a range of offences, including conspiracies to murder, significant drug trafficking and money laundering offences, along with alleged offences of violence.

In South Australia, multiple criminal trials have been delayed pending the Court of Appeal decision.

The case was referred up the Court of Appeal last year by Supreme Court Justice Adam Kimber, who had ruled in a test case that the AFP had not illegally intercepted the messages.

He referred questions of law to the Court of Appeal to seek confirmation his decisions were correct.

The Court of Appeal decision is now expected to make its way to the High Court in Canberra.

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