Much has changed in English cricket since Sajid Mahmood last played for his country, at the 2007 World Cup. That eminently forgettable tournament, coming at the end of a grim winter that also included an Ashes whitewash, was Duncan Fletcher’s final assignment as England coach and Michael Vaughan’s last appearance as a one-day international player.

As with England, Mahmood finished the tournament with his head bowed, conceding 49 runs from 4.2 overs in a thumping defeat by South Africa in Barbados.

In the 2½ years since then, England have had two coaches, failed to reach a final in three more global tournaments and been led by four different captains. It has been a time of substantial change and Mahmood, now 27, believes that he has undergone a similarly profound period of transformation.

Tomorrow, he will begin his journey back into international cricket by boarding a plane for Johannesburg with England’s one-day squad, but he says he barely recognises the callow youth who played eight Tests and 25 one-day internationals between 2004 and 2007.

“I’ve been thinking about it quite a bit recently and I feel like a totally different person now,” he said. “At first, you go into the England team and think everyone is superior. I was thinking, ‘God, I’ve seen these guys on telly.’ Now I’m a lot more confident in my ability. When I go into that dressing room again, I’ll know what I need to do and what I’m capable of.”

When Peter Moores, the former England head coach, arrived at Lancashire as head coach at the start of last season, he compared Mahmood’s career to that of Ryan Sidebottom a few years earlier: brief but unfulfilling experiences at international level, followed by enforced spells of re-education in county cricket. Now is Mahmood’s chance to prove that he has learnt his lessons well and, in particular, that he has outgrown the young fast bowler’s tendency to blow hot one day and cold the next.

“The main reason I wasn’t in the England side was my lack of consistency,” he said. “My levels of concentration were not what’s required at international level. Concentration comes naturally to some, but I’ve always been one of those who’s easily distracted. I was the same at school, always being distracted by something or someone.”

So how has he worked on improving concentration? “Mooresy told me to start bowling in the nets like I do in a game,” he said. “I’d not always found it easy to concentrate in the nets because you’re bowling against your mates. He knew I liked a crack with the lads but said that I needed to put that to one side. Once I did that, I felt like I was getting something from every session.

“Technically not much has changed in my bowling, but in the mind I’m a lot stronger.”

At 6ft 4in, with a loose-limbed action and natural athleticism that Troy Cooley, the former England bowling coach, likened to that of a 400 metres runner, Mahmood has always possessed the raw materials to become a fine fast bowler. The problem was that he was just too raw.

Last season, he was given greater responsibility at Lancashire, often leading the attack, and responded impressively.

“He’s matured as a cricketer and as a person in the last couple of years,” Mike Watkinson, the Lancashire director of cricket, said. “You know now what you’re going to get from Saj on a daily basis. When he last played international cricket, he’d have some good days and other days when he dipped.

“He’s learnt to find the balance between using his natural aggression, while staying relaxed enough to keep his rhythm. He’s less agitated and his concentration is much improved.”

In the absence of Stephen Harmison and Andrew Flintoff, Mahmood has the potential to be England’s quickest bowler. Pace has always come naturally, although part of the maturing process has been to rein himself in.

“I try not to think about how fast I’m bowling now,” he said. “If I’m bowling with rhythm, the pace will always be up in the early 90s [mph]. Before, I’d think too much about bowling quickly and end up bowling slower because the other parts of my bowling would suffer. So the main thing now is to get my rhythm right and the pace will sort itself out.”

That said, a broad grin creeps across his face as he concedes that the fast bowler’s urge to add that extra yard of pace never goes away. “Oh yes, you always want to bowl faster,” he said. “The fitter and stronger you get, you should get a little bit quicker. I’ve been working quite hard in the gym, so I’m hoping in this one-day series I can hit 95 or 96.”

There is indeed a more solid look to Mahmood’s wiry frame these days. “I used to lose a lot of weight during the season because I wouldn’t eat much during games,” he said. “But the fitness guys at Lancashire have had me doing a few light weights while we’ve been batting, and making sure I eat as well. If you keep that weight on, it helps to avoid injuries, and I’ve also got a bit bigger and stronger.”

A more substantial character in mind and body, it will be fascinating to see how Mahmood copes with his second coming as an international cricketer.