The 1998 Real IRA car bomb killed 29 people, among them the mother of unborn twins. A group of retired officers due to give evidence said they would not cooperate until assured that proper support and protections are available.

The move follows the death in recent weeks of a retired former RUC sergeant who is understood to have taken his own life. He had worked on the original investigation, witnessed the devastation first hand and had been suffering from post-traumatic stress disorder (PTSD). He had previously given evidence in a civil case against alleged bombers and was due to appear before the inquiry.

The officers said they were pausing participation “to protect the wellbeing of retired officers, many of whom have already been retraumatised by the process”.

They added they had been “experiencing significant and well-documented pressures linked to the Omagh Bomb Inquiry process”. “These include retraumatisation, renewed psychological distress, uncertainty around legal protections, and the emotional burden of revisiting catastrophic events from 1998,” they said.

“These pressures have been raised consistently with the inquiry, government departments, welfare bodies and elected representatives over a three-year period.”

A spokesperson for the Omagh Police Support Group said: “These issues are not hypothetical. They are evidenced in public domain reporting, inquiry testimony, parliamentary statements and welfare-sector data.”

While not withdrawing entirely, the group said the pause was a “necessary and responsible step”. Future engagement, they added, would depend on safeguards including “clear and independent legal protections”, stable timetables and defined witness-handling protocols.

Public hearings for the next phase, examining how the bombing was carried out and who was responsible, are now expected to begin on September 21 after delays linked in part to disclosure issues involving the Government.