FOR a man who prides himself on keeping things simple, Allan Leighton leads a surprisingly complicated life: chairman of this, director of that, dashing round the country visiting his stores (BHS), depots (Royal Mail), building sites (Wilson Connolly) and what-have-you. He likes to be on boards — nine at last count — but he also likes to be on the move.

Can’t sit still? Ooh, not sure about that, he says, some of his best work is done sitting in saunas and spa baths at Cannons, the health-club chain he also chairs. That’s where he gets close to customers. He likes to pop into any Cannons unannounced, chat to staff, work out, strip off, plunge in and introduce himself to surprised customers. “Hi, I’m the chairman, any comments?” Some would run screaming but there’s method in Leighton’s madness. It’s how he has always worked — “getting close to the operators”.

It is how he helped build up Asda into one of the most successful supermarket chains in the 1990s, and it’s one reason why the government wheedled him into heading the loss-making Royal Mail, where he has been chairman for over a year. The customer responses at Cannons, by the way, are later relayed to staff in an e-mail titled “Feedback from the chairman’s sauna”. Leighton, 49, is not without a sense of humour.

He may need it this week when he has at least one tough decision to make: whether the Royal Mail should take its regulator to the Competition Commission over the restrictions placed on its ability to increase the price of stamps. Too much regulation for Leighton’s liking. Probable outcome? Dunno, he says, in his cheerfully demotic way.

He’s slumped back in a chair in the gym at Cannons’ HQ in New Malden, south London. Tall and lean, with his hair and beard razor-cut to a quarter of an inch, Leighton looks tough, even threatening, but belies it with an easy-going chattiness.

Perhaps more surprising is the way he has parlayed his experience since leaving Asda into creating an extraordinary “super-director” role for himself, pogo-ing around between the likes of Royal Mail, BHS, Dyson, Lastminute.com, Leeds United, BSkyB and more.

He calls it “going plural”; others think it’s spreading himself a bit thin but nobody can deny it works for Leighton. Like a lot of late starters, he feels he has always got more to find out — and to offer.

The Leighton trademark is fast change with a populist touch. Already he has junked the Consignia name at Royal Mail; restructured it from “15 different businesses to five real ones”; stripped away layers of management; vowed to stamp out employee bullying; brought in former FA boss Adam Crozier as chief executive; and announced 30,000 redundancies.

That’s his style, honed from 17 years learning on the hoof at Mars, then his dash for glory at Asda. He tells people at Royal Mail: “It’s straightforward. We collect mail, we sort mail, we deliver mail, and we retail. That’s strategy. Don’t wait for the film, don’t wait for the book — don’t talk to me about anything that isn’t to do with any of those four things.” And the price of letters? Too cheap.

Archie Norman, who hired Leighton as his successor at Asda, once described his protégé’s key quality as “traction”: the ability to make things happen fast. And that’s Leighton’s lure for the many who now use him: bam, in-yer-face, then he’s off to find out what’s happening at the other end of a firm.

It’s why he used to lope around Asda with “Allan — happy to help” on a badge, why the shopfloor loves him — he’s interested — and why, at Royal Mail, he made Crozier spend a fortnight on the beat with posties before he took on the chief executive’s role.

He says he picked that trick up from James Dyson, the vacuum-cleaner mogul, on whose board he also sits. Dyson, who makes all recruits assemble a cleaner on their first day, says Leighton is one of those men obsessed with learning, always asking questions. “Watch his eyes, they’re always darting, always exploring,” says Dyson.

Leighton approached Dyson a decade ago, having read his autobiography, and it’s as if he has now turned that interest — meeting bosses he wants to learn from — into a full-time occupation: Dyson, BHS boss Philip Green, Lastminute founders Brent Hoberman and Martha Lane Fox. “He loves the energy of owner-managed businesses,” says Lane Fox. “He came round in his leather coat and we just clicked.” She adds that he spent his second day at the firm sitting in customer service, helping staff with calls. They loved it.

Yet for an inquisitive man he is strangely uninterested in how he got his gifts. Ask Leighton about his upbringing and the words dry up. He was an only child, went to boarding school then North Oxford Poly, a late developer who only blossomed when he joined Mars after a stint at Lloyds Bank.

“Then a couple of people got hold of me and everything changed: work ethic, the lot. I wasn’t mature till then.” And his mum and dad? Just “ordinary, hard-working people”. His dad managed Co-op shops. That’s it.

Leighton is more stretched now than he has ever been. He says he makes time because he doesn’t do lunch — doesn’t eat breakfast, either, which makes you wonder how he refuels — and avoids all meetings except board meetings. He then cracks a joke about his work-life balance being sorted out: it’s work, ha ha. In short, he’s pretty much a force of nature.

If you are a Leeds fan, you might be reading this with your lip curled. Leighton, who became a fan when running Asda from its Leeds base, has presided as deputy chairman of Leeds United over a stonkingly awful last 12 months: fire-sale of great players, results collapsing, debt problems emerging.

What happened? Can’t comment, says Leighton, as Leeds reports this month. But those dark eyes look pained. “Part of the test of management,” he says eventually, “is when things don’t go right, do you run and hide, or do you sort it out?” Some wonder, though, if he has taken on too much. Should Green’s Safeway bid get through the OFT, that’ll be another chunk of his diary gone. Leaping into the “regulatory treacle” at Royal Mail may seem a bad decision. But Leighton is adamant. “I just thought, this is the Royal Mail, it’s got a quarter of a million ordinary people working for it, and if I could sort it out, it would be a good thing, wouldn’t it?”

Yet he’s not so sentimental that it stops him making 30,000 of those people redundant. “That’s why he’s a good businessman,” says a friend.