Soldiers and their families are aware that in battlefield conditions, there is no absolute guarantee against “friendly fire”, death or injury at the hand of your own or allied forces. Judgment can be blurred by stress; decisions must often be taken at speed. The convoy of tanks from The Blues and Royals attacked in March 2003 by two American A10 Thunderbolts had triple British identification: orange tiles on tank roofs, large Union Flags and thermal imaging reflectors. The American pilot who launched the attacks that killed Lance Corporal of Horse Matty Hull saw the orange tiles and knew them to be “friendly” identifiers; yet three minutes and six seconds later, he had persuaded himself that what he was seeing were “orange rockets” on enemy vehicles. Between the first sighting and the signal from air forward controllers that the convoy he had attacked was British, less than 11 minutes elapsed. There is sick horror in the two pilots’ voices as they get the news: horror, and evident recognition of their personal responsibility. One says to the other: “We’re in jail, dude.”

This we now know, because The Sun obtained and published the cockpit records of the incident that the US had refused to declassify for use in open court. That refusal did not prejudice the outcome of the inquest into Lance Corporal Hull’s death. The coroner, whose responsibility it is to establish the truth about the death, had seen the video record. But the refusal did, he strongly felt, prejudice the need, and the moral entitlement, of the Hull family to be told all that was known about their son’s accidental death.

The Pentagon position is that battlefield data is classified and cannot be released for fear of setting a precedent that could compromise security — even where, as in this case, no military secrets were at issue. This policy is not only too rigid; it is needlessly hurtful both to bereaved families, and to the health of America’s most important military partnership. The US relented in this case for the worst of reasons, to avoid looking foolish as well as stubborn. It would be wise to review the general policy. In cases of friendly fire, the rule should be maximum transparency: the release of all known facts unless there are pressing security reasons for nondisclosure.

The family and the British public now know how Lance Corporal Hull died. They will never know the identity of the pilots. They may never know what, if any, disciplinary action was taken against them. The identities of American service-men are witheld to protect them should they be captured. They are revealed only in courts martial — which normally apply in friendly-fire cases only where there is negligence or wilful breach of discipline.

Fair enough; but this fatal accident should not have happened; there were basic and avoidable errors. The US record on holding its military publicly to account is not good, penalties are suspected of being too lenient, and the lack of transparency has harmed relations with other allies, notably South Korea and Japan. Bereaved families should be told what action is taken. The system may in fact work as the pilots clearly expected it to do, but it must also be seen to work by those who lay their lives on the line with US forces.

An inquest is not a trial. The pilots are not in the dock, nor should they be. People do understand that terrible things happen in war. But they resent being kept in the dark, above all when truth can help to heal the wounds of war. It is not in anyone’s interest to let such resentment build.