'The AFP have just realised I'm live tweeting': ABC journalist lays bare police raid

As Australian Federal Police officers swooped on ABC headquarters at 11.30am on Wednesday morning, the broadcaster's head of investigative journalism was waiting.

Reaching for his phone, John Lyons would respond to the raid in a uniquely modern way: he live tweeted the whole thing.

John Lyons live tweeted as AFP and ABC lawyers combed through documents to determine which documents were eligible to be handed over under the search warrant. Credit: SMH

Authorities typically like to do their work away from prying eyes but, over the course of the day, Lyons blasted out more than 50 tweets, providing a blow-by-blow, behind-the-scenes, photo-rich account of federal police carrying out their search of the ABC newsroom.

He was in the room as the police and the broadcaster's lawyers thrashed out which material had to be handed over.

Posting photos of the search warrant, he revealed it named ABC journalists Dan Oakes and Sam Clark and news director Gaven Morris and captured an "extraordinary range" of subjects.

He revealed that the warrant empowered police and their "digital forensics" experts to access a vast array of documents, data and devices, including journalists' notes, draft versions of the story in question, raw footage, meeting minutes and emails.

A picture tweeted by the ABC's John Lyons as police raided the public broadcaster's newsroom in Ultimo.Credit: John Lyons

Just before 1pm, the cops were onto him: "The AFP have just realised I'm live tweeting the raid and raised it with me. I've said I think ABC staff and others have a right to know about a raid on our premises. I've said I won't use any names of alleged sources or confidential material. They've accepted this."

As of 2pm, the police had downloaded 9214 files that were found in a keyword search. Lyons followed along as they went through them "one by one" to decide what fell within the scope of the warrant and could therefore be taken away as part of the investigation.

"This is a bizarre situation," he tweeted at one point. "I'm sitting in a room with 6 AFP officers conducting a raid who seem to be reading my tweets!"

Stepping away from his live tweeting, Lyons did a brief interview with 2GB broadcaster Ben Fordham and with ABC TV host Patricia Karvelas as the raid dragged on.

He said the police were trying to "send a message" to journalists and accused them of violating the free press.

"I was planning on having a very quiet night watching a game of football but I'll stay here," he said. "It could go on for hours, if not days."