The father of one of the Omagh bombing victims has marked the 20th anniversary of the explosion by urging Northern Ireland’s political leaders to reach agreement so “we can move forward”.

Michael Gallagher’s son Aiden was one of the 29 people killed in the blast, a group which also included a woman pregnant with twins, when a Real IRA car bomb ripped through the Co Tyrone town on August 15th, 1998.

In his speech at an interdenominational remembrance service on Sunday to mark the anniversary of the bombing, Mr Gallagher also paid tribute to all of the victims of the 30-year Northern Ireland conflict, including the members of a Collie Club killed in the La Mon Hotel IRA bombing in 1978.

Victims campaigner Michael Gallagher, who lost his son Aiden in the Omagh bombing, speaks at the interdenominational service at the Memorial Gardens. Photograph: Liam McBurney/PA Wire

The service saw survivors and relatives of the dead gather in the Memorial Garden in Omagh, where they sat around the reflecting pool.

Friends and families of the victims, who came from Northern Ireland, the Republic of Ireland, England and Spain, also laid flowers and wreaths.

The atrocity was claimed by a republican splinter group which called itself the Real IRA.

Mr Gallagher, who is the spokesman for the Omagh Support and Self Help Group, said in his closing speech that as a small province, Northern Ireland was facing its greatest challenges ahead.

“We would appeal to the political parties to seek agreement so that we can move forward,” he said.

“Working alone we can achieve very little, but in collaborative adventures we can achieve a great deal.

“We as a community have paid the highest price, let us not forget we need to make this work.”

‘Courage and leadership’

Former Omagh District Council chief executive John McKinney told the families and friends of those who were killed that they have shown “courage and leadership”.

“It was a struggle, a daily struggle, and I’m sure 20 years is more like 100 years,” he said.

“It’s also encouraging to see such a tremendous turnout, not just today, but over the last 20 years.

“That’s an indication of the spirit of the people of Omagh, the co-operation of the people of Omagh and the support they give and continue to give.

“We can all remember, the hope we had in our minds and hearts from 1995 to 1998, the hope for a better place, a hope that would grow together, a hope for reconciliation.

“Unfortunately, I regret to say, that reconciliation never really happened.

“But if some people actually looked at what is happening in this town and what happens every year, we see the diversity, the interdenominational participation, and people coming together, then perhaps that might give some guidance.”

He added that Mr Gallagher and his group have fought for justice.

The memorial service, titled Out of Darkness, included musicians, readers, singers and clergy from a number of religious denominations.

Children leave flowers during a memorial event marking the 20th-anniversary of the Omagh bombing, at the Memorial Garden in Omagh. Photograph: Clodagh Kilcoyne/Reuters

The Omagh Community Youth Choir performed a piece of music composed by its musical director, Daryl Simpson.

The choir includes Cara McGillion (17), the daughter of Donna Marie and Garry, who were seriously injured in the attack.

PSNI chief constable George Hamilton, former police ombudsman Nuala O’Loan, and Minister for Health Simon Harris were among those attending the event.

A song was sung by Leslie Matthews, who paid tribute to Mr Gallagher, saying he was the reason “we are all here today”.

He added: “I hope and pray that justice will be done in the future.”

Sarri Singer, who founded Strength to Strength, a support group for survivors of terrorism, after she was severely injured in a bomb in Jerusalem in 2003, said that victims share an experience which “bonds them for life”.

She said: “I’ve come to represent victims of terrorism from around the world.

“While I know this week is not an easy week for victims and families, we are all connected and there for each other.

“To the families who have been impacted by the Omagh bomb, you are never alone and your families will never be forgotten.”

Minute’s silence

Prayers were also said in Spanish and Irish, and a minute’s silence was held for all the victims.

Dignitaries hold a minute’s silence during a remembrance service for the victims of the Omagh bombing, in Omagh. Photograph: Charles McQuillan/Getty Images

Mr Gallagher also thanked community services and groups for their help in organising the memorial.

“A communal interdenominational worship has been well supported over the last 20 years and it makes a powerful statement about the community in Omagh,” he added.

Taoiseach Leo Varadkar and Northern Ireland Secretary Karen Bradley were both criticised for their decision not to attend the 20th-anniversary.

In a statement, Ms Bradley said: “I would like to express my deepest sympathy to those affected by the devastating Omagh bombing ahead of the 20th-anniversary this week.

“I hope today’s commemoration ceremony provides comfort to all those bereaved and is marked by hope and remembrance.

“We must never forget the loss that the victims of terrorism live with each day and the remarkable courage of all those affected by such unspeakable acts.”

Speaking on Sunday, Mr Harris said: “The Omagh bombing was one of the most evil acts ever to be carried out on this island and had a devastating impact on so many people.

“My deepest sympathies, and that of the whole Government, are with all the families who have been affected by this atrocity.

“The Government is committed to working with the people of Omagh to pursue every avenue to get to the truth to ensure that those who perpetrated this atrocity are brought to justice.

“I would appeal to anyone who has any evidence that could assist the investigation, even at this 20 years remove, to bring that evidence to the gardaí or the PSNI.”

On Wednesday, a public reflective event will take place at 2.55pm to mark the moment the bomb exploded.

A bell will be rung 32 times to reflect the 31 lives lost, with an additional ring to remember all those who have lost and continue to lose their lives through such atrocities across the world.

The bell will stop ringing at precisely 3.10pm to mark the exact moment of the explosion.

Here is a list of the 29 people who died in the Omagh bombing:

James Barker (12) Buncrana, Co Donegal. Originally from Surrey, England.

Fernando Blasco Baselga (12) from Madrid, Spain.

Geraldine Breslin (43) Omagh.

Deborah-Ann Cartwright (20) Omagh.

Gareth Conway (18) Carrickmore, Co Tyrone.

Breda Devine, 20 months, Donemana, Co Tyrone.

Oran Doherty (8) Buncrana, Co Donegal.

Aiden Gallagher (21) Omagh.

Esther Gibson (36) Beragh, Co Tyrone.

Mary Grimes (65) Beragh, Co Tyrone.

Olive Hawkes (60) Omagh.

Julia Hughes (21) Omagh.

Brenda Logue (17) Omagh.

Ann McCombe (45) Omagh.

Brian McCrory (54) Omagh.

Samantha McFarland (17) Omagh.

Sean McGrath (61) Omagh.

Sean McLoughlin (12) Buncrana, Co Donegal.

Jolene Marlow (17) Omagh.

Avril Monaghan (30) Augher, Co Tyrone (who was pregnant with twins).

Maura Monaghan, 18 months, Augher, Co Tyrone.

Alan Radford (16) Omagh

Rocio Abad Ramos (23), Madrid, Spain.

Elizabeth Rush (57) Omagh.

Veda Short (46) Omagh.

Philomena Skelton (39), Drumquin, Co Tyrone.

Fred White (60) Omagh.

Bryan White (27) Omagh.

Lorraine Wilson ( 15) Omagh.

- PA