Families bereaved by the Omagh bombing have put their lives “on hold” until a judge decides whether to order a public inquiry, a campaigner said.
Hearings in the case finished in July and relatives are awaiting the judgment from Mr Justice Mark Horner.
The 1998 blast was the worst single atrocity of the Northern Ireland conflict.
The dissident republican car bomb killed 29, including Michael Gallagher’s mechanic son Aiden aged 21.
He said: “I took the action and we are on tenterhooks and many families are anxious to hear what that decision is.
“It is 21 years after the bomb and we are still waiting.
“We are on hold here – our lives are on hold.”
On August 4 1998, 11 days before the bombing, the Royal Ulster Constabulary (RUC) received an anonymous telephone call warning there would be an “unspecified” terrorist attack on police in Omagh on August 15 1998.
The force’s Special Branch, which handled intelligence from agents, took only limited action on the information and a threat warning was not sent to the sub-divisional commander in Omagh, an investigation by Baroness O’Loan when she was police ombudsman found.
An RUC review concluded in 2000 that the information should have been passed to the commander.
Mr Gallagher launched his legal action after former Northern Ireland secretary Theresa Villiers decided in 2013 not to order a public inquiry.
She argued instead that a probe by another former police ombudsman, Dr Michael Maguire, was the best way to address any outstanding issues.
The following year, Dr Maguire said Special Branch withheld some intelligence information from detectives trying to catch those responsible for the Omagh bombing.
Mr Gallagher believed his challenge to the Government’s decision not to hold a public inquiry must have made legal history because it was so long-running.
A spokeswoman for the Office of the Lord Chief Justice of Northern Ireland said: “I can advise that the judge has not indicated a date for the delivery of this decision as yet.”