Sir Alex Ferguson terrifies his grandchildren by showing them the belt his former teacher used to beat him with during his school days.
And the ex-Manchester United manager, who said he was usually punished for fighting in the playground, insists his teacher remains an inspiration to him.
Along with several other members of his class, Ferguson gatecrashed Elizabeth Thomson’s wedding and they stayed in touch for the rest of her life.
She left him the leather strap in her will, along with a note that read: “You’ll know more about this belt than anyone.”
And Ferguson, who keeps the belt in his study, wrote in The Times’ education supplement: “My grandchildren are terrified of it. Six from that belt and you were in absolute agony. I used to try to draw my hand away. But that was the sort of punishment you had if you stepped out of line. In my case, it was usually for fighting in the playground.”
Corporal punishment has been banned in Britain for a quarter of a century but was used during Ferguson’s schooldays in the 1950s.
And the 72-year-old, who went on to win 49 trophies in his managerial career, believes Thomson’s methods worked in the deprived part of Scotland where he was raised, insisting her determination rubbed off on him.
He said: "The area of Glasgow I grew up in, Govan, had one of the highest truancy rates in the city. [Mrs Thomson] came from a different world, really. She was from a middle-class, wealthy family, but she had a raw determination about her.
“When she first got to Broomloan Road Primary, she went round to the house of every student who wasn’t in her class that day and said, ‘If your kid isn’t in school tomorrow, I’ll be back at your door.’ Maybe 2,000 teachers turned the job down, turned down that sort of challenge, but she thrived on it. She improved everyone she touched. She actively sought out challenge.
“The three ingredients to Elizabeth, were personality, determination and energy. Anyone who’s in charge of someone else needs those three ingredients. It just won’t work without them.
“When I think about her now, I realise that it wasn’t all about education. Mrs Thomson endeavoured to make you want to be the best you could be. I think there’s part of me that comes from her, that determination and that sense of drive. That ‘never-give-in’ attitude she had about all her students.”
Ferguson also feels his will to win and refusal to accept defeat on a sporting field owes much to his late teacher.
He added: “She had a gritty determination about her; a competitive nature. On a Friday afternoon, she’d always give us an hour of playing rounders. Once, I was batting and I tapped the ball, then did the bare minimum to get to first base.
“‘Ferguson!’ she roared. ‘You tap that ball again and I will have you.’ So I battered the next ball out of sight and ran like hell. She was good like that. She got you performing, you know?”