There is no defence for a verdict that flies in the face of common justice

To the surprise of no one, the Government yesterday rejected the findings of a House of Lords committee into the 1994 Chinook helicopter crash, standing by its earlier conclusion that the two pilots were negligent. The Ministry of Defence said that it had considered all alternative hypotheses about the cause of the accident, but found them "implausible". Its investigators, it said, "were left in no honest or genuine doubt that the pilots were negligent".

The Lords report, published earlier this year, had found that there was insufficient evidence to find the pilots culpable. In so doing, it concurred with the first Defence Ministry inquiry which had failed to identify any one reason for the crash. This latest verdict, however, is the one that counts.

As far as the Government is concerned, the names of flight lieutenants Richard Cook and Jonathan Tapper will go down in the annals of shame. They will forever be the two men whose recklessness caused their own deaths, those of their fellow crew-members and some of the brightest of the Northern Ireland intelligence community.

Yesterday's decision understandably dismayed the families of the pilots. It also infuriated the members of the Lords committee, who felt that their conclusions had been too readily dismissed. More important, it also defied common justice.

For the Ministry of Defence to determine that the pilots were culpable because alternative explanations were "implausible" is nowhere near good enough. It would not be sufficient to condemn a living defendant in a court of law; where a posthumous reputation is at stake, it is completely inadequate. This will be the last judgment on these men's character; it must be just not only beyond "honest or genuine doubt", but beyond all doubt.

The Ministry of Defence also disregarded a guiding principle within the armed forces. Standard practice is to blame pilots for accidents only when the evidence points irrefutably to them. This is for excellent reasons of both truth and service morale; the cause of both will now be impaired.

The Government's need to establish the cause of the Chinook crash is entirely comprehensible. The elite of the Northern Ireland intelligence operation were lost. They were travelling in a helicopter which, given the weather forecast, should arguably never have taken off, by a route that might have been better avoided. Given the number of Chinooks in service, it was crucial also to establish that neither this helicopter nor the Chinook as a class was at fault.

The MoD's conclusions are based in part on a manufacturer's simulation of what may have happened. That is not consoling. The manufacturer, like almost everyone involved, has an interest in someone else taking the blame for a malfunction. Consider the latest dispute about British Army rifles in Afghanistan. If a rifle is too complicated to be easily cleaned and maintained, it is probably not hardy enough for its task. But executive authority, contracts and commissions are all at stake: how much simpler to blame the rank and file serviceman.

With accidents such as the Chinook disaster, it is sometimes impossible to identify a single cause. The evidence so far disclosed points to misjudgements, to unfortunate conjunctions of circumstances, and to one outright folly – the decision to transport so many irreplaceable intelligence operatives on one flight. In the absence of cast-iron proof, it is unjust to heap all the blame on two men who cannot defend themselves. It also discourages people from asking further questions.