Sir Alex Ferguson reveals the one thing in life that he 'fears' and is trying to prevent happening

Manchester United's legendary manager Sir Alex Ferguson has opened up on his one big fear in life in a rare interview.

The Scot opened up on just how much he misses life at Old Trafford, where he won 13 Premier League titles, during a sit-down with BBC Breakfast.

Fergie also lifted two Champions League crowns, five FA Cups and four League Cups during his illustrious 27-year stay at United.

But having left the club in 2013 and enjoyed a life away from the Premier League limelight, Fergie explained how the potential threat of dementia is one that worries him having entered his eighties.

"I'm 82, obviously I worry about it. Generally my memory is quite good, pray the lord and touch wood it will stay that way," he said.

"But I worry about it, 100 per cent. I would be lying if I said anything different.

"I read a lot, I do quizzes a lot and I think that helps.

"You have those YouTube quizzes, 100 questions, and I think if I don't get to 70 per cent I'm struggling."

Ferguson was speaking about his work with a dementia charity, with England icons Nobby Stiles, Sir Bobby Charlton and his brother Jack all examples of famous footballers who were diagnosed with the illness prior to their respective deaths, while United great Denis Law suffers from Alzheimer's.

Sir Alex himself suffered a brain haemorrhage six years ago and was forced to go under the knife in an emergency surgery at Salford Royal Hospital.

Having made a successful recovery, the legendary boss was rocked by the loss of his late wife Cathy last October after a serious illness, with Fergie referring to her as his 'bedrock'.

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Despite such a serious setback in his personal life, Ferguson is still regularly seen attending United matches.

On missing life at the club, Fergie added: "I have been retired 11 years now so you find a way of adjusting. Yeah, I miss it sometimes.

"I think the first year after retirement, I went to the European final and I said to Cathy 'this is what I miss' - big games, the European games.

"So then I went to most of the European finals because I find something I can relate to, something I would liked to have done every day.

"Because these are the big events that United should always be involved in."