Joe Sealey prised the lid off a Tupperware box and fished out one of about a dozen audio cassette tapes stacked inside.

It had ‘ghost’ written on it. ‘He was sure he’d seen a ghost once,’ smiled Joe, flicking through others, mostly labelled with the names of football teams and occasions, such as ‘FA Cup final’.

It was the first time he had opened the tub since it landed in his possession by chance, along with the draft of a book titled Definitely Mental.

Les Sealey (left) kept a clean sheet as United beat Palace 1-0 in the 1990 FA Cup final replay

Les's son Joe Sealey is pictured holding a manuscript of his dad's autobiography, Definitely Mental

Sealey (in green) celebrates with Sir Alex Ferguson after helping him win his first trophy at United

Joe had been watching his son, Remi, playing for Manchester United Under 12s at Carrington in 2014 when he spotted Les Clitheroe, his former Sunday league team manager, a schoolteacher and an old family friend.

They began to chat. ‘I’ve got your dad’s book,’ Les told him. ‘No, he didn’t write a book,’ Joe replied.

Well, actually, he did. The inch-thick printed manuscript sitting on the table, faded and bound in a dog-eared blue folder, is Les Sealey’s autobiography.

It was put together in 1994 by Clitheroe from the interviews on the tapes, and it charts the popular East Ender’s adventures as a goalkeeper with nine clubs, from Coventry to West Ham.

It has never been published. Joe has not listened to the tapes. He has not heard his father’s voice since he died suddenly, 15 years ago, and knows it will be a tearful experience.

He has read the book, however, and he leafs through the loose pages to the 1990 FA Cup final replay when Manchester United beat Crystal Palace.

That was United’s first trophy under Sir Alex Ferguson. It was also Les Sealey’s finest hour, although he seldom spoke of it publicly out of concern for Jim Leighton, who was dropped after the 3-3 draw in the first game.

Sealey notes in Clitheroe’s book that he writes with Leighton’s permission. The next chapter is Leighton’s own account of events, also told with brutal honesty in his own book, In the Firing Line, published in 2000.

Sealey (right) celebrates United's Community Shield victory with Bryan Robson (centre) and Ryan Giggs

A Tupperware box containing cassette tapes used to put together Sealey's autobiography

The manuscript contains a picture of Sealey playing for Manchester united

Ferguson’s bold decision twisted two lives in different directions. It changed the course of United history but it did not end a friendship between two goalkeepers. The bond, if anything, strengthened.

When he discovered he was playing, Sealey searched for Leighton to console him and found him in tears. After the match, he gave him his winner’s medal.

Leighton slipped it back into the pocket of Sealey’s blazer. Sealey found it and handed it to Sir Bobby Charlton, asking him to pass it back to Leighton at a later date.

The goalkeepers remained tight long after leaving Old Trafford. They often spoke on the phone and Leighton helped carry the coffin at Sealey’s funeral in 2001.

In the replay, United’s Lee Martin scored the only goal and Sealey kept out Palace as they tried to unsettle him.

He was 32, with more than 350 games behind him, but this was only his third United appearance. It was the biggest night of his life and he was not the sort to blow it.

‘Palace players were trying to annoy me in the tunnel,’ he wrote. ‘Being a profound and deep-thinking person, I told them to f*** off. One of them called me an ugly b******. “Less of the b******”, I said.’

He was ‘clattered’ by Mark Bright and ‘flattened’ by Andy Gray. ‘Palace hit me as hard as they could but they didn’t realise I was playing for my career.’ He was on loan at United and expected to return to Luton Town.

Sitting in the Wembley bath afterward, he spoke to Ferguson, who agreed to let him go straight home to Essex rather than travel back to Manchester.

Sealey begged a lift from photographer Lawrence Lustig and, as they crawled round the North Circular Road, he wound down a window to wind up a nonplussed United fan.

‘What’s happening? What cup? Who was the goalkeeper? How did he play? Did he really make a difference? What’s his name? Did he have one of these?’ At which point Sealey waved his United shirt.

‘He knew he’d been had. He looked at me and said, “It f***ing well is you, isn’t it?” but you could tell he was thinking, “What’s Les Sealey doing in a 1.6-litre Sierra on the A406. Shouldn’t he be sipping champagne in a posh hotel?” ’

Fame did not concern Sealey. He went home for a ham sandwich and a cigar, then to a pub quiz because he had promised to be there.

Life, however, would never be quite the same. The next day he told his sons he would buy them anything they wanted. Joe and George wanted water pistols.

As they walked to the toy shop a Jaguar pulled up, the driver climbed out, stood and applauded. They were mobbed in Chingford. The world wanted to know more. Offers reached £20,000 before newspapers realised his story was not for sale.

Crystal Palace striker Mark Bright clatters into Sealey during the FA Cup final replay at Wembley in 1990

United defender Gary Pallister checks on Sealey, who was making his third appearance for the club

Sealey rushes out bravely to thwart Ian Wright (right) after being included in United's XI

Ferguson returned with a one-year contract and the medal. Leighton did not want it. It is now on loan at the Manchester United museum with his other medals. This would not be Sealey’s last cup final drama.

Back at Wembley in the 1991 League Cup, Sealey gashed his left knee in a collision with Sheffield Wednesday’s Paul Williams. It was cut to the bone but he refused to go off and, after he hobbled through the final 12 minutes, it was stitched in the dressing room.

At Heathrow, as the team waited for their flight, Sealey collapsed. He was taken to Middlesex Hospital for emergency surgery. The wound had become infected and a surgeon told him that had he made the flight, he would have lost the leg — and possibly his life.

Less than four weeks later Sealey was fit to face Barcelona in the European Cup-Winners’ Cup final. Or, at least, said he was.

Sealey’s courage and I’m-your-man determination was well received. When he returned to Old Trafford after a year at Aston Villa, his cult status was undiminished.

Playing for United mattered. He was thrilled to have this chance late in his career and it shone through. Sealey’s wife, Elaine, recalls him dancing around the room when the call came from Ferguson.

His big personality projected a presence. He was brash, wise-cracking and a positive influence in the dressing room.

‘Exuberant and fun to be around,’ said Mick Harford, a team-mate at Luton. ‘When I first walked into the dressing room he got up, shook my hand and said, “Pleaty (manager David Pleat) tells me you’re a bit of a hard man”. ‘I said, “That’s for you to decide”.

‘Les called himself “The Cat”, we called him “Tiddles”. So you know who was hardest. Les won his last fight by 100 metres.

‘He was very good — one of the best I played with. He reminded me of Pat Jennings, making saves with his feet, but he knew how to keep the ball out of the net.’

After winning the FA Cup, Sealey bumped into Pleat at an England game. ‘You never rated me, did you?’ he joked.

Sealey pictured with wife Elaine and two sons Joe (right) and George

Sealey started after his good friend Jim Leighton was dropped following the 3-3 draw in the first game

Sealey places the FA Cup on his head as he celebrates Manchester United's famous victory

‘It wasn’t true,’ said Pleat. ‘I did rate him. He was a line-keeper like Hugo Lloris. He relied on tactical know-how. The players liked him. He was cocky. He thought he was the world’s best goalkeeper.’

Harford recounted one episode when Luton were hammering Newcastle 4-0 on Kenilworth Road’s plastic pitch.

‘The ball’s gone to Les who flicked it with the outside of his foot, on to his knee, caught it and rolled it out,’ said Harford. ‘The Newcastle players weren’t happy. They were getting stuck into Les on the way off.

‘At Newcastle for the return we’re 4-0 down and Gazza’s doing flicks inside his own penalty box. Kenny Wharton’s sat on the ball in his own half — and they’re all looking down the other end for Les.’

Sealey was moulded in the goalkeepers-are-crazy era.

‘If you chipped him in training he’d chase you and try to fight you,’ said Garry Thompson, a room-mate in the early years at Coventry. One infamous mix-up between the pair ended with a Thompson own goal in a League Cup semi-final against West Ham. Sealey dashed out as Thompson knocked it past him.

‘The loudest man in the world never said a word,’ said Thompson. ‘The next thing I knew he was standing next to me, the ball was in the net and Les just whispered, “Keeper’s”.

‘He took taking the p*** to an art form. He’d join one side of an argument for the comedy value, depending on where he thought he’d get the most laughs. By the end he’d be on the other side.

‘People fell out with him but never for long. He was a funny guy. It makes me laugh just thinking about him.’

Sealey signed for West Ham in 1994 and spent seven years there, split by Leyton Orient and Bury spells

Sealey shakes hands with legendary Manchester United manager Sir Matt Busby

Les's son Joe was a goalkeeper in West Ham's youth ranks when his father died of a heart attack at 43

Sealey was dubbed ‘Mr Angry’ for his tendency to fly into a rage for little reason, often at team-mates.

Coventry’s assistant manager Ron Wylie once asked Elaine how she could be married to such a lunatic. ‘He wasn’t like that at home,’ she said. ‘He was a real family man, very funny, he loved being at home.’

Sealey would often call his sons downstairs to make him coffee and keep him company. ‘He wasn’t the mad man people saw on the pitch,’ said George.

He would spend hours under the bonnet of an old car. Sealey went into business with car dealer Paul Dimery while at Luton. He was one of football’s Del Boys, bringing sheepskin coats and leather jackets from east London to sell to the players from the back of his car.

When a mobile-phone salesman arrived at United with free hand-sets for the players, Sealey talked him into a deal which included free calls, too.

He signed for his beloved West Ham in 1994 and spent seven years there, split by brief spells at Leyton Orient and Bury.

Harry Redknapp appointed him goalkeeping coach but he was registered to play into his 40s.

He was once sent on as a winger at Arsenal and told to ‘make a nuisance of himself’. Redknapp said: ‘Les was the life and soul. He’d lift you when you were down.’

Sealey’s entrepreneurial instinct led him into property — and into business with Jonathan Barnett and David Manasseh, sports agents who wanted to expand into football.

He helped them establish contacts with players and Stellar Group grew into one of the world’s leading football agencies, with Gareth Bale its star client. Barnett and Manasseh, to their credit, have never forgotten Sealey’s role and remain close to his family.

In the 1991 League Cup final Sealey gashed his left knee but refused to come off and hobbled on for 12 minutes

Sealey (third right) returned to Manchester United for the 1993-94 season

Sealey died in 2001, a few months after leaving West Ham, where both Joe and George were goalkeepers in the youth ranks. He was just 43 and had not been ill. Doctors called it a billion-to-one chance.

He had been tiling at one of his properties in Southend when he felt unwell. Somehow he drove himself to hospital, parked outside A&E and died from a heart attack as he got out of the car.

Joe had been told only two weeks earlier that he would have to quit football after a series of shoulder injuries. The devastating news that his career was over was followed swiftly by the death of his father.

Only the promising career of his son, Remi, has drawn Joe back to the game. Now 33, he watches United at home and will be at Wembley on Saturday.

George, 30, also had shoulder and back injuries, left West Ham, had a trial at Crystal Palace and played briefly for non-League Thurrock. Like his brother, he had quit the game by the age of 21.

Both admit they fell out of love with football after their father died — a shame, because football will always love characters like Les Sealey, who lived for the game and flourished in its unique environment.

Joe is not sure what will become of the book. He tidies the sheets and slides them into the blue folder. The tapes are returned to the tub and the lid is replaced.

He thinks he will see it published one day but is unsure when.