Howard Aspinall
Shocking experience!
I relate to the instance when yours truly had acquired a magneto with turning handle from some junk shop. This was intended for testing car spark plugs, but it also had another use. The ground floor studies at school had wooden doors with metal handles. They also had metal heating radiators.
Having previously been kicked out of physics by pop Regal who didn't like my face and thought I was thick, I brought this magneto in and connected the high voltage terminal with a bit of wire to the study metal door handle, and its case to the heating radiator.
When footsteps were heard coming along the corridor, I would "lie in wait" inside the study with its door firmly shut, quietly cranking the magneto. The effect was to make the door handle electrically live and anyone touching it whilst I cranked it would get rather a nasty (but theoretically safe) electric shock. A few lads including Scotty Henderson came and grabbed the handle, had the pain, then saw the funny side on finding out what it was.
All went quiet for ages, then I heard foosteps approaching. They slowed, and I could hear them coming up to the study door. I quietly cranked the magneto. The handle dropped momentarily then returned to its usual position without the door opening. A sort of choking sound followed, then silence. Then a voice I knew only too well said: "Aspinall, what the hell are you doing in there?" OOps it was the boss....old RR himself! I had to follow him to his study, but didn't have to bend over for the anticipated. Instead, he actually saw the funny side of it, and let me off with a caution. It didn't seem politic to use the magneto for such "nefarious" purposes again!

Roderick Harron asks:
OK, I have a question after all these years.
Who the hell was it that spat on Mr. Bradys lambretta?
Remember the whole school was assembled for that question, sometime in 59 I think. Was it you Geary or Pickard may be.