The Police Ombudsman has drawn a blank over who phoned a warning that a gun and mortar attack would be mounted in Omagh two weeks before 29 people lost their lives in the Real IRA bombing.

Despite an investigation lasting more than 12 months the Ombudsman has told relatives that his staff have been unable to pinpoint who made the call on the August 4 1998.

The caller warned of a gun and mortar attack on police in the town and relatives have complained that it should have triggered a major RUC operation to seal off the area.

It has been suggested that the call from a phone box in Beragh about 10 miles from Omagh was made by a serving police officer at the time but no evidence has been uncovered to support the report.

The Ombudsman has told relatives that his officers were unable to establish if the call was made by a police officer and simply couldn’t identify who was responsible.

Godfrey Wilson whose 15 year-old daughter Lorraine was killed in the bombing said the outcome of the Ombudsman’s investigation was a disappointment.

“It’s one of the mysteries of the Omagh bombing that may never be solved”, he said. “The call on August 4 warned of a gun and mortar attack on police in the town but nothing was done. Had a plan been put in place to deal with that threat the town could have been sealed off a lot quicker and maybe many lives would have been saved.”

The Omagh man whose daughter was working in the Oxfam shop when the bomb exploded said there had been 27 previous attacks by the Real IRA across Northern Ireland and feels that more weight should have been given to the anonymous call.

“Two weeks previously Banbridge was blasted by the Real IRA bombers so I can’t understand why when the call came in contingency plans weren’t made. Why were troops not ready to be called out the weekend of the bombing given the threat level? I suspect that a political deal had been done with Sinn Fein to keep troops off the streets but we may never know exactly what happened with Omagh.”

Meanwhile Downing Street is expecting to receive a report within days on how much the Government’s secret listening station knew about the Omagh bombing.

The Intelligence Services Commissioner Sir Peter Gibson is expected to hand in his findings on the intercepted mobile phone calls made by the Real IRA bombers on their way to the town and how the information was shared.

Sir Peter has been investigating the issue of phone intercept intelligence associated with the 1998 bombing after relatives gave the Government a one week deadline to hand over the information in September. The Prime Minister announced that Sir Peter would conduct a review of all the intelligence information held by GCHQ in Cheltenham and write a report within three months.