TODAY is the 25th anniversary of one of the most tragic and most mystifying events of the Troubles in Northern Ireland and one of the few times, thankfully, that that long conflict fatally impacted onScotland.

The Chinook Helicopter Disaster on the Mull of Kintyre on June 2, 1994, was the largest single loss of life in any incident in the Troubles, yet it is seldom viewed in that regard because the 29 deaths were caused by an accident and not a terrorist or British military operation.

Yet all of those who died, including the pilots, were participants in the security services dealing with the Troubles, and the reason the 25 passengers were on the helicopter was to attend a high-level meeting taking place in secret in Scotland that very much had to do with a major development in the Troubles – namely, the peace process.

The death toll also made it the worst peacetime disaster to befall the Royal Air Force.

Most facts of the disaster are undisputed. At 5.42pm on Thursday, June 2, the Boeing Chinook mk2 helicopter forming Flight ZD 576 took off from RAF Aldergrove near Belfast Airport, heading for Fort George near Inverness. On board were 25 male passengers, almost all of them involved in the police and intelligence services, as well as the crew of four.

The passengers were heading to a security conference and, just 17 minutes into the flight and enveloped in thick fog, the Chinook ploughed into a hillside on the Mull of Kintyre, some 800ft above sea level. The 51ft-long helicopter caught fire and all but one of the men aboard were killed instantly, the last victim surviving only a few minutes.

Ten senior Royal Ulster Constabulary officers died, including six senior Special Branch officers, along with nine Army officers and six members of the civil service unit that investigated the funding of paramilitaries. Effectively, the intelligence services’ top personnel in Northern Ireland were almost all killed in the crash.

The four dead crew members were all special forces aircrew, including the two pilots, Flight Lieutenants Jonathan Tapper, 28, and Rick Cook, 30.

Immediate speculation was that the flight had been sabotaged, but this was quickly ruled out. The UK Government contributed to the conspiracy theories that arose because they issued a “D” notice banning the naming of the dead intelligence officers.

An RAF Board of Inquiry was quickly set up and it concluded that the cause of the accident could not be definitively established. But on reviewing the evidence, two senior Air Vice Marshals decided otherwise and blamed the “gross negligence” of the two pilots.

The rush to judgement by the authorities was unwise, unseemly and very unjust. In no time at all it emerged that there had been serious problems with the particular type of Chinook helicopter, the Mk2, which crashed on Kintyre.

For whatever reason, these problems were kept from the initial board of inquiry and it seemed at first as though the verdict of pilot error would stick.

Then, after hearing 12 days of evidence, Sheriff Sir Stephen Young ruled after a Fatal Accident Inquiry at Paisley in 1996 that the pilots were not guilty of negligence and concluded the cause of the accident would never be known.

THE RAF refused to change its verdict, but the authorities reckoned without the tenacity of the families of the pilots and the other deceased passengers. They began a long campaign of trying to get at the truth, and several journalists and politicians were soon persuaded that the whole affair stank of a cover-up.

Investigations showed that the Chinook Mk2 had an engine system known as FADEC, which the Ministry of Defence’s own experts had concluded was “positively dangerous”.

Then it emerged that a special RAF team had been set up look into the airworthiness of the Chinook flight. The team’s report said that five previous Chinook crashes over six years had called into question the effectiveness of overall “management and maintenance” of the helicopter fleet.

It took 17 years for the British Government to admit that the pilots were not at fault.

The then defence secretary Liam Fox made a public apology in the House of Commons in July 2011 after retired judge Lord Alexander Philip reviewed the case along with former Tory secretary of state for Scotland Lord Michael Forsyth, former Labour Scottish secretary Helen Liddell and the then LibDem MP for Gordon, Malcolm Bruce.

Lord Philip and the three-strong panel was unanimous in saying that the findings of gross negligence should be set aside.

The major point in the 99-page report was that the air marshals were wrong and had received incorrect legal advice at the time.

Finally the families got justice, but to this day there are researchers and investigators who argue about the cause of the disaster, and about whether it was pilot error or instrument failure. Views are entrenched, to say the least.

Yet the initial response by the RAF and MoD is another example from recent history, if any were needed, that the British state is perfectly capable of utter mendacity, even when dealing with absolute tragedy.