The British Government should immediately announce a new investigation into the Omagh bombing, the MP for the area has said.

Sinn Fein West Tyrone MP Orfhlaith Begley said a High Court judge’s verdict that there are “plausible arguments” there was a “real prospect” of preventing the 1998 Real IRA atrocity will leave further questions for the families of the victims.

The Omagh bombing was the worst incident of the Northern Ireland Troubles, killing 29 people including a woman pregnant with twins.

This recommendation is a tribute to the determination and courage of the families of all those killed in the atrocity and their long campaign for truth and justice

Mr Justice Horner has called for new investigations on both sides of the Irish border.

Ms Begley welcomed the High Court ruling.

She said: “This recommendation is a tribute to the determination and courage of the families of all those killed in the atrocity and their long campaign for truth and justice.

“The judge’s comments that there is a real prospect the bombing could have been prevented will undoubtedly add to the distress of the families and leave them with further questions.

“That is why it is vital that the British Government act on the judge’s recommendation and immediately move to announce a full, human rights-compliant investigation into the exact circumstances of what happened.

“Grieving families should not have to face any further delays or face any more obstacles when it comes to finding out the truth about the deaths of their loved ones.”

SDLP West Tyrone MLA Daniel McCrossan said there must now be a full public inquiry into the bombing.

He said: “My heart goes out to the families of all those who died in the Omagh bombing.

“The ruling that there was a real prospect their loved ones’ deaths could have been prevented will be a devastating blow and no doubt reopen old wounds.

“We are over 20 years on from the bombing, but for many in this area the hurt still feels as real as if it were yesterday.

“There must be a full public inquiry to establish once and for all exactly what happened in Omagh that day.

“Families still have many unanswered questions and have been let down by the justice system time and time again. They have the right to know if their loved ones deaths could have been prevented if greater police and army action was taken against the paramilitaries involved.

“There can be no more excuses, the truth must be heard and justice must be done.”

Ulster Unionist MLA and former victims’ commissioner Mike Nesbitt said the full ruling by Mr Justice Horner will need to be scrutinised when it is released.

He said: “My thoughts today, as always, are with the victims and survivors of the Omagh atrocity of 15th August 1998.

“Whatever detail is contained in the full ruling, the fact remains that the Omagh bomb was the work of the terrorists who chose to make it, transport it and detonate it in a market town on a busy August Saturday afternoon.”

Alliance Party councillor for the area Stephen Donnelly said: “We must not forget, dissident republicans were the cause of the Omagh bomb and are the ones who need brought before the courts to pay for their crime. That wider context still needs investigated.

“Today is a major vindication for the families and their ongoing campaign pursuit for truth and justice. The bombing was the darkest hour in the history of Omagh and its shadow persists to this day.”