There have been what media are calling "extraordinary scenes" at today's hearing of the Independent Inquiry relating to Afghanistan chaired by Lord Justice Sir Charles Haddon-Cave.
Veteran's Minister Johnny Mercer MP had referred in his written statement to warnings given by unnamed military friends that there might be something in the allegations circulating about unlawful killing's by some British Special Forces personnel in Afghanistan. But when appearing as a witness he refused to give the inquiry the names of those informants.
Two informants were said not to be direct witnesses to the allegations, and another potentially was.
One can sympathise with Mr Mercer on his reluctance to, in his words, "burn" his private sources. He did say that he would reflect on warnings from the Chair, and he should certainly take legal advice. Each informant might consider whether they can reasonably resolve the difficulty themselves.
Perhaps of greater significance is the revelation that he had growing suspicions over several years that, again in his words, "something stinks".
It has been pointed out that Mr Mercer himself, reportedly already knowing something of the Afghanistan allegations, appeared at times quite dismissive of sincere concerns - right or wrong - about the Overseas Operations (Service Personnel and Veterans) Bill which he sponsored.
We know it isn't easy to find the right course between the wish to protect armed forces personnel from unnecessary or prolonged investigation and litigation, and the need for crimes to face justice.