Botham: England's real test starts in South Africa

He said: "The acid test comes now with South Africa. They are rated number one in the world and England have got a big point to prove. If England have the full team and the right team, and pick the right players, who knows.

"I think we can beat them but we need all our big guns fired up."

With Andrew Flintoff gone it is time for the next generation of players to develop and Sir Ian identified Stuart Broad as the key man for the future.

He said: "They've got to move on. The guy with the big winter is Stuart Broad. There's been a lot of hype and expectation but I think he's found his forte now in the bowling department. He's not going to be an out and out quick bowler but he can do an extremely good job, similar to Glenn McGrath.

"He's accurate, he's got good control and variation. If he concentrates on that pattern of bowling he'll be very effective, plus he's got the height as well."

England disappointed in the one day series against Australia as well as falling short in the ICC Champions Trophy last week. Sir Ian, who played in two World Cup finals, is puzzled as to why they struggle in that form of the game.

He said: "We played well in the first couple of games in the ICC Trophy, punched well above our weight in the rankings, and everyone was pleasantly surprised. But then we slumped towards the end.

"I don't know what it is with England and one day cricket. I suppose the question is maybe now we're starting to pick the right players. That might have a bearing.

"There are a few one day specialists but in the past we haven't picked them. Then we have picked too many but I think they are just about getting towards the right balance now.

"Andrew Strauss and coach Andy Flower have a lot of ideas and a lot of ambition. They won't like the way England have played one day cricket for a while now so they'll look to rectify that."

Sir Ian, 53, was in Canary Wharf to launch his new book, My Sporting Heroes, a personal selection of 50 sportspeople who best demonstrate the 10 qualities, such as leadership and skill, he feels are necessary to make it at the top level.

With the likes of Gareth Edwards, Sir Steve Redgrave and Sir Alex Ferguson all featured it's a pretty exclusive list and Sir Ian revealed it was difficult to keep it limited to 50.

He said: "It was very difficult. In fact, it could easily have been 150.

"Dean Wilson, who wrote the book with me, and I argued quite a bit on some of them, but I think we ended up with a pretty respectable 50.

"There are a lot of qualities that all the guys in the book have somewhere in there, but certain players stand out. Alex Ferguson stands out for leadership, Ryan Giggs for durability, Geoffrey Boycott for determination."

Sir Ian, who played 102 test matches and is still England's leading wicket taker with 383 victims, was a ferocious competitor - particularly against Australia - but had a surprising choice when it came to choosing his own outstanding quality.

He said: "I think humour. It's so important. Sam Torrance was a great Ryder Cup captain because of his humour. He relaxed everybody with a few old stories or whatever.

"I think humour is a part of it and I'd say it was probably one of the big factors in my game. That and my enthusiasm."

And would he swap his glittering cricket career for that of one of his sporting heroes?

He said: "I suppose the golfers of my era who are still playing, still touring and enjoying it. That's the one great thing about golf, the longevity of it. It just goes on and on.

"But the grass is always greener on the other side of the fence. I'm very happy where I am."

Sir Ian, who was knighted in 2007, has been a tireless fundraiser for Leukaemia Research and was in Canary Wharf last month to take part in the annual BGC Partners charity trading day on behalf of the LRF. He is keen to take part every year.

He said: "I loved it, it was great fun. We did some rather big deals, although I don't know what we ended up with charity-wise but I think we've done very well.

"I'll come back next year if I'm available."

Before then he has another of his famous charity walks to undertake. Since 1985 he has twice walked from John O'Groats to Land's End as well as across the Alps to raise money for Leukaemia Research.

The next one will happen in April, although details of the route have yet to be finalised, and Sir Ian is preparing himself for another battle with the blisters.

He said: "It's the 25th anniversary next year of my first ever walk and the 50th anniversary of Leukaemia Research. It's a massive year for LRF.

"They are finalising routes, working with local authorities. I think they've got it pretty much set out. My daughter's running it, and she knows not to tell me too much."

For more on Leukaemia Research visit lrf.org.uk.

My Sporting Heroes by Ian Botham is published by Mainstream, priced £18.99.