He left a pause for this news to impress and continued thoughtfully: “It seems impertinent of me to sit here all these miles and all these years distant from the action and say to the chief protagonist, ‘I know what happened. I know your secret,’ but I have access to information of a special nature. Records, sealed even to the participants, are opened to a policeman who knows how to play his cards right. And I haven’t hesitated to rig the deck to get to the bottom of this festering sore. Some sources, like the King’s Own Yorkshires, were pleased to share with us the details of one or two of their heroes and villains without any strong-arming.”

“I’m thankful to hear that at last someone in authority has been seriously looking into the case. It took a few corpses to claim your attention, but I do believe we may have gotten there.” The tone was almost teasing.

Redfyre responded with an equivalent lightening of mood. “You’ve no idea what I’ve suffered in the pursuit of the truth! I’ve skirmished with the master of a college, danced a fandango in the High Street, battled with a squad of pipistrelle protection ladies . . . I’ve even toothed a jellied eel.”

“And they say a policeman’s lot is not a happy one.”

“People are always telling me, ‘Ah yes! But this is Cambridge.’ Sometimes, fancy footwork is of more use than a truncheon and a helmet, and I’ve put on a display of my most impressive boleos to crack this case. We each have our special advantages, Captain Dunne. Between us, we should at last begin to make some progress, solve a few mysteries. What do you say?”

He waited for the grin and nod of assent. “Now, your original request when you came in this morning, if I remember, was for a sketch pad? Prescient of you!” He took a pad from a drawer and found a pot of pencils. At the invitation to sketch in the environs of the cabin, including stabling arrangements, latrines, the railway line, the river, points of the compass and estimated off-plan positions of Kimberley and the army HQ, the captain obliged with speed and neatness. He drew his last line, put down his pencil, turned the map towards his interrogator and gave Redfyre a challenging but not unfriendly look.