Arnold, now 71, has seen his charges come home to gold for almost 40 years now. He estimates Greene's effort here Thursday night (September 1) was the 66th major medal won by an athlete he has guided.

Since he sat in the Munich Olympiastadion and watched his then athlete John Akii-Bua, from Uganda, win the 1972 Olympic 400m hurdles title in a world record time of 47.82, this sharp but kindly figure has been inspiring and challenging athletes to achieve their potential all around the world.

Twenty years later Arnold had an Olympic champion he wasn't expecting. It was supposed to be Colin Jackson, by general consensus the finest 110m hurdles talent present at the 1992 Barcelona Games, but the gold ended up with the Canadian who had come over to train with Jackson under Arnold – Mark McKoy.

The man Arnold had trained for 10 years had failed; success had gone to the man he had taken on late - despite the whispers of those who disapproved of the Canadian's past, in which he had admitted taking steroids as part of the group including Ben Johnson that was coached by Charlie Francis.

"Some people had condemned me without having the courage to say anything to my face," Arnold (pictured) told me at the time. "I didn't seek any assurances from Mark when he first came. But I know when athletes are up to something, and he's back on the straight and narrow. In the present system it's very easy to condemn people. Perhaps my ethics are a little more Christian. Forgiveness is an important aspect.

"I didn't know whether to laugh or cry after the finish," he added. "There wasn't much to be said right then - just well done to Mark and bad luck to Col. I don't know how much Colin's rib injury contributed, but defeat hurt him inside and still hurts him now. It will dog him for the rest of his days. The most impressive thing to me, though, was that the following day he was bright and breezy and ready to get on with things again."

Jackson gave his talent the tangible reward it deserved with two subsequent world titles and a world record of 12.91 which lasted for more than a dozen years.

But Arnold, formerly Britain's national coach, but now operating as a UK Athletics Senior Performance coach at the University of Bath, has not dealt solely with hurdlers. His expertise as a sprint coach, and in particular in the business of getting swiftly out and away from the blocks, helped Jason Gardener win world and European 60m titles in more recent years.

That expertise was also tapped into by the former world and Olympic champion Linford Christie who, though coached by Ron Roddan, would often join Jackson in starting sessions under Arnold's watchful eye.

Arnold's is a gift generously bestowed. For example, in 1992, during a starting session in which Christie was involved, Michael Rosswess, a runner of huge talent but indisciplined technique who had reached the 1988 Olympic 200m final as a 23-year-old, was invited along.

The coach noticed that Rosswess was not adjusting his blocks to gain the maximum advantage, and altered the set up. "It only took about five or six seconds," Rosswess recalled a couple of years afterwards. "The difference it has made to my starting has been huge."

Four years ago I visited Arnold in Bath to see him in operation with some of his latest group of athletes – Gardener and fellow sprinters Craig Pickering, the 20-year-old European junior champion, and 19-year-old Ryan Scott.

Arnold, a white-haired figure in comfortable tracksuit trousers and trainers, was sitting in the long gallery window of the University's indoor track, winter sunlight slanting across him, as his sprinters prepared themselves for the session. He may have been on the periphery of the action, but he was the central figure.

It was a measure of how effective Arnold's training sessions were, and also of how effectively the internal competition operated, that all three men looked as nervous as if they were about to race for real. Pickering shifted from one foot to the other, occasionally blowing out hard. Gardener, back after a year ruined by a back problem, clapped his hands hard, twice.

"On your marks," intoned Arnold, before activating the bleep which set the pair off through cameras set at 10 and 30 metres. Afterwards, both wheeled around and made straight for the machine which had already printed out the incontrovertible proof of their performances.

"Craig, that was a much better series for you," said Gardener as he inspected what looked like a till receipt. Arnold was close at hand. "That's pb [personal best] territory for you, Craig," he added.

This is the human alchemy of Arnold's coaching groups.

Balancing the claims of closer rivals had long been something at Arnold (pictured with Gardener) was adept.


He accepted that upsets would always happen where competitive athletes are involved. "I'm a professional coach in a hard sport where objective results matter," he told me. "So if Craig kicks Jason's backside, or young Ryan Scott kicks Craig's, that's fine by me. There is a pecking order, but it sorts itself out.

"When Craig came back after the Lee Valley run, Jason was the first to congratulate him and shake his hand. Both of them have got a brain between their ears. It's only when you've got dumbos that you get the aggravation.

"They are a friendly lot here. It was the same with Colin and Mark - they would always have a laugh and take the mickey out of each other. But it all finishes when you get to the line."

Athletics, ultimately, is a harsh and lonely sport. Arnold knows this.

"My confidence, it is not unfounded," Greene said in the wake of a victory that added a world title to the European and Commonwealth golds he has already amassed. "It comes from knowing I've done the hard work before I get here."

Arnold has never been one to suffer fools gladly, however, and it always does to listen carefully to what he says, given his predilection for lobbing verbal grenades.

"Malcolm is a great coach to be around," Pickering said in Bath. "He's seen it all before. You could run a world record, and he would just say, 'Well done.' To be working under someone with such experience gives you lots of confidence. Fortunately, he has not needed to have a cross word with me yet. But you can't mess around because he won't take it."

He added, when asked what it was that Malcolm does which encourages successful competition: "There isn't really any secret: we just work exceptionally hard. We find out what things we are weak at, and work at them until they become our strengths.

"Malcolm installs a really strong character in you as well, as he takes no crap whatsoever. Before Jason won the World Indoors in 2005, he had torn both his groins, and was struggling to walk. He was umming and ahhing about whether to compete, until Malcolm said: 'Stop fucking around, just go and fucking do it!'


Arnold's latest combo is yielding similar success. While Greene (pictured) has been cutting a swathe through the world's opposition, his younger training partner, Jack Green, has already become European under-23 champion.

But Green was far from happy with failing to reach Thursday's final.

"It was embarrassing," he said. "I'm really disappointed because I shouldn't have been beaten. I messed up at hurdle seven but that is not to abnormal for me but in general I felt like I got into it a lot better.

"I got a telling of from my coach Malcolm Arnold after the heat who said that it was the worst run that I've ever done in my life."

You get the feeling that young Mr Green will be back in time to do better. The Arnold Effect – it just keeps on going...

Mike Rowbottom, one of Britain's most talented sportswriters, has covered the last five Summer and four Winter Olympics for The Independent. Previously he has worked for the Daily Mail, The Times, The Observer, the Sunday Correspondent and The Guardian. He is now chief feature writer for insidethegames. Rowbottom's Twitter feed can be accessed here