The family of murdered civil rights lawyer Pat Finucane has issued legal proceedings against leading Ulster Unionist MP Ken Magginnis. In April this year Maginnis criticised calls for an independent inquiry into the killing and Geraldine Finucane's refusal to co-operate with an inquiry by John Stevens, deputy commissioner of the Metropolitan police, into the loyalist murder of her husband.

Maginnis claimed that "It was an open secret that Pat Finucane was inextricably linked to the IRA and committed to its objectives. No collusion was required to draw him to the attention of loyalist murderers."

Pat Finucane was shot dead at his Belfast home in February 1987. Since that time, his family has mounted a campaign for an inquiry into alleged collusion between the Royal Ulster Constabulary and his loyalist killers.

Finucane's brother John was killed in a car crash while on an IRA operation in 1972 and two more brothers, Seamus and Dermot, have both served sentences for terrorist offences. Though prominent in carrying out the legal defence of Republicans, the family has maintained that Pat Finucane was not a member of the IRA and was not active in the Republican movement.

Maginnis's remarks were condemned by the Irish government, nationalist politicians and the Criminal Bar Association. A week after they were made, however, Sir John Hermon, the former RUC Chief Constable, backed Maginnis, claiming that Finucane had been associated with the IRA and had used his position to "act as a contact between suspects in custody and republicans on the outside".

The comments of Maginnis and Hermon were designed to cast doubt over the motives for Geraldine Finucane having refused to co-operate with the Stevens Inquiry. In reality, Geraldine Finucane's reluctance to do so stems from the fact that Stevens headed an earlier inquiry into collusion between the security forces and loyalist gunmen 10 years ago, the findings of which were covered up.

The Finucane family's insistence that only a public inquiry, independent of the RUC, can uncover the truth about her husband's murder is backed up by recent developments.

Northern Ireland authorities are currently embroiled in legal action against an Irish journalist, Ed Moloney, seeking to force him to hand over notes of an interview he conducted eight years ago with the prime suspect in the Finucane murder.

William Stobie, the man arrested by the second Stevens Inquiry team, announced in court that he was a police informer at the time of the Finucane murder. He said that he had told the RUC that someone would be assassinated on the day of Finucane's murder, though he claimed not to know who the target was.

In the course of a judicial review against the court order to hand over his notes, Moloney has said that nine-year-old files held by the RUC would prove that they knew of Stobie's role in the murder at the time and took no action against him.

While designed to quell the calls for a public inquiry into Finucane's killing, the arrest of Stobie has raised damning questions about both the RUC and the Department of Public Prosecutions (DPP). In an article for the Sunday Tribune last weekend, Moloney said:

"In particular two aspects of the DPP's behaviour in relation to Stobie require explanation. One is why the DPP directed a ‘not guilty' verdict when Stobie, charged on what he claims were false, Special Branch-inspired arms offences in 1990, threatened to publicly reveal that he had warned the Special Branch about the Finucane murder and they had done nothing.

"The second is the reason why Stobie was not charged with the Finucane murder in 1990 when, after disclosures to the RUC by former journalist Neill Mulholland, he was held for seven days and questioned 32 times about the Finucane murder."

Moloney has also revealed that the Stevens inquiry team had considered issuing a gagging order on Stobie's interviews, in the event that a request for access by Moloney's lawyers last week had been successful.

Citing "well-informed sources", Moloney says that "detectives last week let it be known that if the Sunday Tribune's legal attempts to obtain the documents had been successful they would have sought an order making the records subject to a Public Interest Immunity Certificate (PIIC)".

This device was first used to hide evidence at a 1988 inquest into the elite British military unit, the SAS's shooting of three alleged IRA members in Gibraltar. It would have made it impossible for the documents to be passed informally to lawyers acting for Moloney.