In the injury-forced absence of his great rival Iwan Thomas, who last week underwent ankle surgery, Richardson is arguably Britain's best hope for a medal in Seville. As for next year's Olympics, Roger Black has declared that his protege, 27 next Monday, can win gold. "It is always in the back of my mind," says Richardson, "that these are the two most important years of my life." Duly inspired, he is currently in tip-top form and raring to go. Moreover, he gave himself a shot in the arm a year ago, the benefits of which have yet to wear off. It was, I should swiftly add, an entirely legitimate shot in the arm, namely a historic victory over the legendary Michael Johnson - over, in fact, one of the best 400m fields ever assembled - at the prestigious Bislett Games in Oslo.
Richardson's time that day, a personal best of 44.37 seconds, was a fraction of a second outside the British record. More significantly, it was achieved on the inside, in lane one, which made victory even sweeter. "When I saw the lane assignments, it blew my mind," Richardson recalls. "Lane one on any track is not ideal, but Oslo is only a six-lane track, so the bends there are especially tight." He tried to have his lane changed but the officials were unyielding.
"So then I had to work on changing my mindset. To think how good it would be if I could pull off a good time from lane one. I got out of the blocks really well, and did exactly what my coach told me not to do. He'd told me not to generate too much momentum from the start because I'd find it difficult to negotiate the curve. And I did have to brake, and could see them all running away from me. It was an awful feeling. I was dead last, and I remember thinking `there's no way I'm finishing last.' So I put a charge in, and suddenly I realised I was amongst them, and thought that if I managed to hang on I could finish second."
Instead, Richardson nicked it, with Thomas second and Johnson a relatively distant third. While it would be nice to say that the great man did not take his defeat lying down, that is precisely how he took it, lying motionless on the track for more than 20 minutes afterwards. It was only the second time he had been beaten in 64 400m races over nine years. "I don't know whether he was tired or just trying to get his head round what had happened," says Richardson. "Maybe he was under-prepared, or a bit lackadaisical. I didn't talk to him. He keeps himself to himself and I don't know any of the quarter-milers who have a good relationship with him."
Reportedly, Johnson was spotted in a bar that night bonding with a certain Jack Daniels. "Yeah," says Richardson. "I heard that too."
We are chatting in Richardson's flat in Windsor. He is an affable, articulate man, with a nice line in imagery. Overcoming his lane assignment to beat Johnson that day in Oslo was, he has said, like "asking David to take on Goliath without his slingshot." And by doing so, he fulfilled the promise that he has always shown but sometimes failed to deliver. In fact, barely a month later, he reverted to type by performing poorly in the European Championships in Budapest.
"I over-raced in the run-up," he says. "By the time I went over there, I wasn't fresh physically, and certainly not mentally. I messed about in the rounds, which was stupid, because the rounds are the way to establish your rhythm and feel your way into an event. The final was a disaster. I blasted the first 200m, went off way too quick. But I think I have gained from it.
"As Daley [Thompson] said to me, `You're a lucky man. Most people have to wait a year before they can redeem themselves, you've got the Commonwealth Games.' And I treated the Commonwealth Games very professionally. I ran the rounds well and got beaten by the better man in the final. Iwan ran 44.52 to my 44.6. It was very close."
Last year, Richardson's rivalry with Thomas was one of the dominant features of British athletics. This year, Thomas is conspicuously absent. Has that, in any way, blunted Richardson's competitive edge? "Not really. I was looking forward to some great tussles with Iwan on the domestic scene, but you have to see this year and next from a global perspective."
Accordingly, he has employed every legal trick in the book to ensure that he can compete with, and hopefully beat, the world's best quarter- milers.
Through his mentor, Roger Black, he has even been having sessions with the hypnotist Paul McKenna.
"I've been concentrating hard on the mental aspect," he explains. "I've been doing some semi-hypnotic stuff with Paul, and also some stuff with the sports psychologist Pete Cohen, basically visualising myself in lots of different scenarios. In your mind you make your lane bigger and brighter than everyone else's. You get into a very relaxed state and do this visualisation so then you feel as though you've got all options covered, and whatever happens in the race - for instance if someone sets off like a nutter - you've been there 1,000 times before."
To the outsider, there is a touch of the Eileen Drewerys about all this. But visualisation is becoming one of sport's orthodoxies, deriving from the increasingly common belief that mental rather than physical sharpness divides champions from also-rans. It is not a particularly new-fangled notion, however. Pat Cash, for example, ascribes his 1987 Wimbledon victory, in large part, to visualisation. And neither he, nor Richardson, are men of fanciful disposition.
Besides, the mental preparation is backed up by a formidable physical training regime. "With the 400m," Richardson explains, "you need a lot of the characteristics of the world-class sprinter, so you have to develop strength and power, but you need endurance as well, so you do a lot of aerobic work to make sure the heart and lungs can cope." He then outlines his winter training schedule, and I get a stitch just listening. "On Thursdays we do a big gym session at the army barracks at Aldershot. A really hellish routine. All sorts of torturous stuff."
Richardson believes that he copes with this rigorous schedule largely because of the work ethic instilled by his parents. His father, from a desperately poor background on the Caribbean island of Anguilla, came to Britain in his teens, and slaved away on the production line at Mars.
Richardson's mother, also from Anguilla, became a nurse. "I have never met anybody more determined in my life and I probably never will," says Richardson.
Between them, to their eternal credit, Ashton and Lorna Richardson scrimped and saved enough money to send their two children to private school. There, young Mark did well academically, became head boy and excelled in sport.
His colour, he says, was not an issue at school, nor has it been since. I ask him to name his sporting heroes. "Muhammad Ali," he says. "That documentary about him, When We Were Kings, is amazingly inspiring. Also, Michael Jordan. And Jesse Owens, who had a strength of character I can only dream about." His heroes, I point out, are all black. "So they are," he says. "It's the first time I've realised it."
Richardson's best sports at school were athletics, basketball, cricket and rugby. On the rugby field, in fact, he was fast developing into a brilliant wing. But his head was turned by the heroics of Carl Lewis in the 1984 Olympics. By the time he went to Loughborough University, to study sports science and recreational management, he was committed to athletics. By then, indeed, he had finished fourth in the World Under- 20 Championships, no mean feat for a 16-year-old.
Richardson's career has since progressed in fits and starts. There has been some awesome running, interrupted by devastating injury and, as in Budapest last year, the odd dash of complacency. For now, however, he seems to have a firm grasp on the baton passed on by Roger Black as Britain's premier quarter-miler. In fact, it is probably fair to say that he is currently one of the top three in the world. And speaking of batons, he is also, of course, an essential and popular component in Britain's 4x400m relay team.
"There tends," he says, "to be a really tight-knit community among the quarter-milers. If you're in the Sub-Three Club (for members of the elite quartets which beat the magic three-minute mark) you get this ring. And we all get on well. Apart from one exception there are no massive egos, which is one of the reasons the team has been so successful for so long. We all wear the same kit, on the track and off, we have a good laugh, in fact it can sometimes be quite difficult for the guys on the fringes of the team."
Still, if this cliquishness helps Britain to win medals, long may it last. Richardson, indeed, would like to build it up further, by introducing a poker school and recreating some of the epic card games of the past. "I've heard all the stories but I missed out," he says ruefully. "There used to be a lot of gambling on the team but it was before my time. Daley, Roger, Tom McKean and those guys used to play a lot of three-card brag. I'd love to get some poker going. It keeps you relaxed and it's a good way of killing time without expending much energy."
Put like that, it sounds as if poker should become obligatory for British athletes. In any case, there is certain to be a full house in Seville next month. Let us hope that Richardson produces at least one running flush.