The UK government has rejected calls for it to release classified evidence relating to the 1998 Omagh bombing, the most deadly single event in the course of Northern Ireland's troubles. 29 people - including one pregnant with twins - were killed in an attack later admitted to be the work of the Real IRA.

The refusal comes in the light of an inquiry into how much intelligence services knew about the bombers. The Northern Ireland Affairs Committee report - published earlier this week - said too many questions remain unanswered and that there should be a fresh investigation into whether the state withheld vital information from detectives.

Accusations similar to these have dogged the government since a 2008 edition of Panorama claimed that the intelligence services had intercepted details of the bombing via tapped 'phonelines but did not pass this information onto the police; had they done so the likelihood of a successful detonation would have been greatly reduced. There are also questions surrounding the investigation itself and whether enough was done to catch the perpetrators.

Thus far no-one has been successfully prosecuted over the bombing in criminal proceedings; South Armagh man Colm Murphy had been found guilty in Dublin's special criminal court but his conviction was later quashed. Another man was cleared in a separate trial in 2007. Only in a landmark civil case - where the burden of proof is not as high - have the relatives of the Omagh victims received any semblance of justice.

It could be that there are genuine fears that national security could be compromised should such information be released, particularly in the wake of ongoing militant activity within Ulster. But given that only two years ago the Province's Policing Board admitted that no one will be charged over the massacre unless fresh evidence is found the need for justice must still be regarded as absolute. Submitting the details of intelligence to an investigating committee behind closed doors and away from media intrusion would at least be a step in the right direction; it's also more than likely that withholding such information will merely serve to reinforce the suspicion that the role of the intelligence services in the bombing was not without flaw.

Labour have been rightly proud of their achievements in helping to bring about peace in Northern Ireland, from the signing of the historic Good Friday Agreement to the restoration of devolved government in Belfast. Now it is time the party's leaders led the way helping to bring about justice, too.