The Police Service of Northern Ireland is demanding that the Sunday Tribune's Northern Editor, Suzanne Breen, hands over all material relating to stories she has written on the Real IRA or else it will take legal action under the Terrorism Act.

The PSNI arrived at Breen's Belfast home last Monday, giving her three days to hand over phones, computers, disks, notes and other material relating to two articles she had written on the paramilitary organisation.

They want material relating to the Real IRA's claim of responsibility for the murder of two British soldiers at Massereene barracks, and to an interview with a Real IRA Army Council representative in which the group admitted killing Provisional IRA informer Denis Donaldson and threatened to murder more soldiers and police.

Breen said: "I wont be complying with the PSNI's demands. Compromising sources undermines the freedom of the press. Journalists and police do different jobs. Our role is to put information into the public domain. If a journalist becomes a gatherer of evidence or witness for the state, they cease being a journalist."

Sunday Tribune Editor Nóirín Hegarty said: "This paper fully supports its Northern Editor. Our stories were clearly in the public interest. We stand firm in upholding journalistic ethics and the protection of sources, and we will continue to do so to the highest level."

The Sunday Tribune has received strong support from the National Union of Journalists (NUJ). General Secretary Jeremy Dear said: "If the police and security services believe they can force journalists to become part of intelligence-gathering operations, the very future of independent journalism will be put at risk.

"An investigative journalist's job is to expose the truth. They can only do that if their sources know they can speak openly and in confidence. The authorities must recognise the special nature of journalistic material and respect Suzanne Breen's right to keep her sources confidential."

NUJ Irish Secretary Séamus Dooley added: "The Sunday Tribune has a strong record of defending press freedom. We welcome the stand taken by the newspaper on this issue."

British Irish Rights' Watch has written to Chief Constable Hugh Orde, complaining about the PSNI's actions.

Its director, Jane Winters, said: "Journalists can't afford to pick and choose which sources to protect. Any journalist who allows themselves to be coerced into revealing a source does the whole profession a disservice because they create the public perception that journalists as a whole can't be trusted to maintain confidentiality."

Professor Brice Dickson of Queen's University's law school said: "It's essential to the running of a healthy democracy that investigative journalists be allowed to go about their perfectly lawful activities without being impeded or constrained by police. What the PSNI are proposing to do is, in my view, a perversion of the Terrorism Act."