There is a moment when a door opens and lets the future in, and increasingly it looks as though a door opened for the England team when Alastair Cook arrived as an emergency replacement in India. Cook’s century on debut in Nagpur, followed by a composed innings of 89 in his first Test appearance on home soil, suggests that this precocious youth is here to stay.

The striking thing about Cook is that doors have forever been opening and letting him in. He was just 14 years old when he was summoned out of class at Bedford School and asked if he would make up the numbers for MCC, who had arrived for a match a man short. Despite being four years younger than many of his team, Cook had been miffed at being left out of the school XI; he had trained with them and had been playing junior cricket for Essex for two years.

It was a no-brainer. “I was dragged out of double physics and asked if I wanted to play,” says Cook. “Double physics or cricket? It wasn’t the hardest decision I’ve had to make. I walked into the changing-room and they said, ‘You’re batting three’. Very poignant as it has turned out (he is batting three for England now). As I walked outside, a wicket fell. I went out and scored a hundred.”

The school didn’t leave Cook out of the XI again. He was an automatic selection for the next five seasons. In his penultimate year, he averaged 93 and scored seven centuries, and in his final year his average rose to 160, boosted by two doublecenturies.

After leaving school in 2003, Cook thought about university — a route that his two brothers would take — but before deciding whether to go to Durham or Loughborough he opted, like many students, for a gap year. But unlike most students, he did more than just travel. After leading England to the semi- finals of the Under-19 World Cup in Bangladesh, he was given an extended run with Essex’s first team and within weeks he had scored a maiden first-class century against Leicestershire.

“It was too good an opportunity to miss,” he recalled on Friday at Chelmsford after his first practice session since the Lord’s Test. “Essex said that I would start the season, and I felt I had to give it my best crack. After that, instead of going to university, I went away with England A to Sri Lanka. Sitting here now, I think I made the right decision, even if personally I missed out on three years of putting reality on hold.”

How sweet. He is so young (Cook is only 21 years old) that he doesn’t yet realise that by opting for the life of an international sportsman he has actually put his life on hold for as long as the whole adventure lasts.

Then, of course, three months ago came England, pulling him out of an A team tour of the West Indies to fill the breach in India.

How does he make each step up look so effortless? “I’ve always tried to treat every game the same, as though it was just another match at school or for my club. I don’t put a big emphasis on the moving up. I almost ignore it, really. The standard goes up, but you raise your game as well.

“Mentally, the biggest thing is to not put too much pressure on yourself. Just try and enjoy it because it will never happen again. That and stay focused on what you’ve got to do rather than getting carried away with trying to be something else.” He also talks about “banking” self-confidence ahead of the next challenge. He says that that was what his double- century against the Australians did for him last summer, giving him the belief that he was good enough to play Test cricket.

Those who have watched Cook’s progress know he is something out of the ordinary. James Foster, his Essex teammate, has known Cook since he first played for the county second XI at 15. “He has always been very composed and had good gameplans,” says Foster. “He’s a bright bloke anyway but he’s got a really good cricket brain. He stands at slip next to me and comes up with really intelligent suggestions.

“He’s also one of the best players of the short ball I have ever seen. I have never seen him get out to it. The big test is how you shape up after a bouncer and he is always right in behind it. And if he has a bad game, he has shrugged it off in 10 minutes.”

Three years ago, Nadeem Shahid was captaining Surrey second XI when Cook took twin centuries off them at The Oval. “It was the first time I’d seen him, although coming from Essex I had heard about him,” Shahid recalls. “It was a good pitch but we had a decent attack. What I remember vividly is how good he was through midwicket with a straight bat. Balls on middle and off stump he hit there like a rocket.