OTU 1966. Commandant, Col. 'Ringo' G....s, has a habit of taking a stroll through cadets lines, preceded by his labrador dog.
One afternoon, cadets sitting around outside rooms polishing boots, brass etc, when labrador appears at one end of lines. Sharp-eyed cadet spots it, calls "Stand fast!" in anticipation.
Ringo appears at other end of lines, to find cadets at attention or saluting his dog.
Extras all round.