I was on the Visual Bomb Aiming Course at Bomber Command Bombing School at RAF Lindholme in April 1963. We were told the story of what had happened there a few weeks before. Their version was : There had been a Staff Contiuation sortie which had an extra pilot on board, who was allowed by the instructor to drop a couple of bombs. The target was an old Tank Landing Craft, but on the night in question the electric lighting on the target was u/s. So, Gooseneck Flares were sited in each corner.
The run in to the target featured an arrow of electric lights pointing to the target. There was broken cloud cover in the area. Unfortunately the "Bomb Aimer" misidentified the lights on a nearby roundabout as the arrow, and when at the right time the "Target"appeared through the broken cloud he duly dropped a 28lb Smoke/Flash Bomb. The pub carpark was illuminated by a light in each corner giving the same visual appearence as the real target. The bomb was "Good" and struck one of two cubicles in the Ladies toilet. Fortunately the unoccupied one.
The letter of apology from OC BCBS included the phrase "It was a Flash in the Pan Occurence"