Image copyright AP Image caption Scene of the Omagh bombing, the worst atrocity of Northern Ireland's Troubles

A bid by two men to overturn a landmark civil ruling that found them liable for the Omagh bomb has been rejected by the European Court of Human Rights.

In June 2009, Liam Campbell and Real IRA leader Michael McKevitt were two of four men found liable for the atrocity.

The civil action was brought by relatives of some of the 29 people killed in the 1998 bombing in the County Tyrone town.

The relatives were awarded £1.6m in damages.

No-one has ever been convicted of murder in relation to the car bomb.

Campbell and McKevitt took their case to Europe, arguing that the civil trial in Belfast High Court had been unfair.

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They claimed that due to the severity of the charges the court should have applied criminal, rather than civil, standards of proof.

Seven judges at the European Court of Human Rights unanimously rejected the case.

The Omagh bomb was the biggest, single atrocity in the history of the Troubles in Northern Ireland.

It happened just four months after the Good Friday Agreement was signed.

The death toll included nine children, three generations of one family, and a woman pregnant with twins.

Image caption In 2009, Michael McKevitt, Liam Campbell, Colm Murphy and Seamus Daly were found responsible for the bombing in a landmark civil trial

7 July 2011

In 2009, a judge in Northern Ireland found Campbell and McKevitt liable for the bombing, along with Colm Murphy and Seamus Daly.

In 2011, the Court of Appeal upheld the ruling against McKevitt and Campbell.

Murphy and Daly were successful in upholding their appeals and were ordered to face a retrial of the civil case. They were subsequently found liable for the bombing at a retrial in 2013.

In their submission to the European Court of Human Rights, Campbell and McKevitt claimed the admission of evidence from an FBI agent who was not available for questioning was unfair.

However, the court found that the judge in the civil case had fully considered the need for appropriate safeguards, given the witness absence.

It was also found the defendants were given an adequate opportunity to challenge the agent's evidence and that the judge gave due regard to the appropriate considerations when deciding what weight he attached to the evidence of an absent witness.

In regard to Campbell and McKevitt's claim that the judge should have applied a criminal standard of proof, the court found that this was not necessary because the proceedings had been for a civil claim for damages.

The court found that the Northern Ireland court's findings were not arbitrary or unreasonable and that applicants had not demonstrated that their trial was unfair.