Relatives and victims of those injured and killed in the Omagh bomb atrocity will have their first formal meeting with the North's Chief Constable Sir Hugh Orde.
The meeting follows a failure by the families in their bid to have talks with the head of MI5, Dame Eliza Manningham-Buller. They wanted to meet her to discuss allegations that the security service withheld intelligence months before the bombing that either Omagh or Derry were to be possible targets.
Dame Elizabeth told the families she had nothing to add to Sir Hugh's statement that no relevant intelligence which could have progressed the inquiry was kept back.
Michael Gallagher, whose son Aiden was among 29 murdered in the dissident republican strike on Omagh, will meet Sir Hugh and Chief Superintendent Norman Baxter, the detective in charge of the investigation, with the other families tomorrow.
They are expected to urge police to go after more suspects. So far only south Armagh electrician Sean Hoey, 36, has been charged with killing those caught up in the August 1998 blast. He is due to go on trial in September.
Their frustration has been intensified by the criminal offensive against the Islamic militants who murdered 191 people in the March 2004 Madrid train bombings. More than 100 people have been held in connection with the attacks, with at least 20 still in custody.
Charges have also been brought against several men accused of involvement in the London bomb plot weeks after 52 people died in the July 7 2005 suicide attacks on the capital. "More people north and south of the border should be charged with Omagh," Mr Gallagher said.
"I don't think there's been the degree of co-operation between the police forces which the families have been led to believe, and that's for political reasons.
"The greatest fear the families have is that both Governments will come to an arrangement which legitimises these terrorist crimes. "The victims' haven't been listened to."