Two child-made paper aeroplanes folded from the British and American flags rest side by side on a school desk, suggesting a shared journey whose consequences lie beyond the innocence of the gesture.

Ben Roberts-Smith’s arrest proves nothing about British troops, but it does show that even elite and decorated special-forces soldiers can be subjected to ordinary legal scrutiny, making it harder for the UK inquiry into alleged SAS killings to be dismissed as futile, unfair or impossible.