Australian associate editor Cameron Stewart has told a court that “police politics” pursued by former Victoria Police chief Simon Overland was behind an Office of Police Integrity decision to forge a criminal case against the alleged source of a Somali terror leak.

At the conclusion of his cross-examination in the Melbourne Magistrates’ Court this morning, Stewart sought leave to point the finger at Overland and the OPI for going after VicPol Africa specialist Simon Artz due to their bitter internal feud with the Australian Federal Police.

“I wonder to what degree that decision was fueled by the toxic high-profile atmosphere that was injected into this case from day one by Simon Overland when he made it very clear that he did not agree with the Federal Police’s decision to brief The Australian on the story of Operation Neath,” Stewart told the court.

Overland had made public statements on the day the Neath raids occurred criticising the AFP drop that led to copies of The Australian plastered with Stewart’s pre-written scoop being available at least three hours before warrants were executed.

“I think that police politics in this case has done no favours for Mr Artz who was in my opinion a minnow in the chain of events that led to the story on Operation Neath,” he said. “The real leaker in Operation Neath … is the Australian Federal Police.”

Asked by defence counsel Bill Stuart what he meant, Stewart was blunt: “They [the AFP] are the ones that leaked the prime information that there was an alleged plot to carry out a terrorist act in Australia.”

Artz has been charged with eight offences including wilful misconduct and is facing a committal hearing following an OPI investigation into the initial leak, that allegedly occurred five days earlier at Southbank.

Stewart said he had not “pumped” Artz for information when the duo met for a coffee on July 30 2009, and that he had simply asked “what was happening” in his source’s current work. He recorded some details of the chat on a series of Post-It Notes.

The result of the chat was this bare-bones yarn, filed just hours after the meeting, that focused on Somalis in Melbourne channelling funds offshore to assist the al-Qaeda linked al-Shabbab.

After the AFP’s media unit were made aware of its content, they promised Australian editor Paul Whittaker a more fulsome briefing in exchange for delaying publication. The Quill award-winning scoop detailing planned suicide attacks on Sydney’s Holsworthy army base — “Army base terror plot foiled” — appeared on August 4. Last year, three men were found guilty over the plot and a further two were acquitted.

Stuart disputed the suggestion Artz had planted the seed and said Stewart had simply “used him” to “confirm the true source” — presumably someone else in the Australian intelligence community.

In a dramatic conclusion to his evidence, Stewart also made a personal statement backing Artz, a trusted confident who he had spoken to several times over the years.

“In my mind [he was] a good man, in the sense that I know he was well regarded by the African community with which he dealt with a lot … I know that he was well regarded in legal circles and I know he was well regarded amongst his colleagues,” he said.

“My personal belief, for what it’s worth, is that he certainly doesn’t fit the mould of a corrupt cop, on the contrary he’s a man who made a misjudgement on one day of an otherwise stellar 20-year police career, and I personally find it abhorrent the OPI chose to recommend criminal charges against Mr Artz for a matter for which could surely have been dealt with by internal disciplinary procedures within Victorian Police.”

The Australian has consistently criticised the OPI’s phone tapping powers and has been accused of running an editorial campaign to dissolve its operations.

The paper’s editor-in-chief Chris Mitchell wrote to the OPI after its report on the leak was compiled saying that he would “use every journalistic and legal measure available to pursue what can only be described as an outrageous fabrication”.

Earlier, Stewart was questioned on his paper’s print runs, saying that he told the AFP that he was “not qualified” to understand when individual editions would physically had been on sale. He had simply passed on a note from Whittaker that copies would not be available before 3am on the morning of the raids.

The committal is expected to wind up tomorrow with evidence from two employees of Andrew Denton’s Zapruder’s Other Films, which was filming a documentary on the AFP at the time. Magistrate Peter Mealy will then have to weigh whether there is enough evidence to refer the case to trial. If convicted, the genial Artz faces serious jail time.

*Read Friday evening’s account of Cameron Stewart’s first day in the witness box here