Sir Alex Ferguson could have been lost to the game forever had it not been for a hat trick against Rangers at Ibrox, the United manager has revealed.

The Reds boss was back in Glasgow this week to visit his old school, Govan High, before delivering a lecture the next day to students at Glasgow Caledonian University, where he holds an honorary degree.

Sir Alex spoke passionately about leadership, drawing on more than three decades of experience as a football manager - including 23 years at United of course. But it was the story of how close he came to shunning professional football that caused the biggest stir.

“I was part time at St Johnstone. In a reserve game against Airdrie I broke my eyebrow, cheekbone and nose and was out for months. They put this massive plaster cast on my face," recalled Sir Alex.

“After I came back from the injury I played three reserve games. We lost 8-1, 7-0 and 9-2. I said that’s it - I’m finished. I took out papers to emigrate to Canada.

"On the Friday (night before the match against Rangers), my brother’s girlfriend phoned up my manager at St Johnstone and told him I had the flu. But when I arrived home from a regular Friday night at the swimming baths with my mates, my mother tore into me and said, ‘I’ve had a telegram from your manager - get down to the telephone booth and call him.'

“The manager said, ‘Report to the Bath Hotel tomorrow, you’re playing against Rangers’. I scored a hat trick and became the first player to do so against Rangers at Ibrox – it changed my life. I became a full time footballer in the summer and never looked back.”