Loyalist lifer Trevor McKeown could be called to the public inquiry into the murder of Catholic lawyer Rosemary Nelson.

Four years ago he claimed rogue RUC officers directed him to the spot where Rosemary Nelson parked her car and urged him to shoot her there — less than two years before she was eventually killed by a loyalist car bomb.

McKeown says two officers asked him to kill the human rights lawyer while he was being quizzed over the murder of 18-year-old Bernadette Martin — an allegation they strenusously denied.

He said: "I would be willing to speak at the inquiry as I have nothing to hide. I am very worried about my security in giving evidence.

"These officers wanted me to shoot Nelson. They made that clear. I didn't agree with them that she should be killed and just said nothing.

"When I was arrested a detective said to me: 'You shouldn't have killed that 18-year-old girl, but Rosemary Nelson instead'. He said it would be easy for me or other loyalists to shoot her.

"Another detective was sitting in the room and just sat there as if he agreed while the first detective was telling me he wanted Rosemary Nelson dead. That was made clear to me."

Exactly 20 months after the alleged incident in July 1997, Mrs Nelson died from horrific injuries suffered when the LVF planted a booby-trap bomb under her car in Lurgan. The Red Hand Defenders — a cover-name for the LVF in mid-Ulster — admitted responsibility.

Since her death there have been persistent allegations of security force collusion in the murder, which is now the subject of an inquiry headed by retired judge Sir Michael Morland.

Ironically, McKeown's trial for murdering Bernadette Martin started the day mother-of-three Mrs Nelson was murdered on March 15, 1999.

Two English police officers have already interviewed Trevor McKeown inside Maghaberry Prison about his claims that an RUC officer urged him to murder the Catholic solicitor.

The police team investigating Mrs Nelson's case later found that the officers identified had been questioned years before as part of an internal inquiry into Mrs Nelson's allegations that RUC officers were threatening her while interviewing her clients.

But no evidence was found to uphold the complaints, which the policemen denied.

As the inquiry opened at Craigavon Civic Centre in recent months counsel to the inquiry Rory Phillips QC raised Trevor McKeown's allegations and hinted they may be raised later in the case.

He said: "There was, for example, some years after the murder, an allegation made by a man described as a convicted loyalist killer that he had been incited by police officers to murder Rosemary Nelson.

"Now, at present it is not clear to what extent we will be able to explore this matter in the evidence, and I, therefore, propose to say very little more about it at this stage, save to say this: this was a matter again investigated by the murder investigation team; the allegations were denied and no charges were brought as a result.

"However, it was with these sorts of allegations of criminal conduct in mind and as one of a series of measures designed to encourage witnesses to be open in their evidence to the inquiry and to ensure that the inquiry received the fullest disclosure and co-operation from those with material of relevance, that the inquiry, during the course of 2005, sought from the then Attorney General, Lord Goldsmith, a limited evidential undertaking."

The undertaking declares that no one giving evidence shall have it used against them later in any criminal proceedings.