Justin King is known for his sunny ebullience. It matches his company’s orange logo. The chief executive of UK supermarket group J Sainsbury even looks sunny with a ready smile crammed with bright white teeth and a permanent tan. “It’s rust,” he quips. In fact, it is the remnant of a recent holiday.

Archie Norman, former chief executive of rival supermarket Asda, which employed Mr King in the early 1990s, describes the 49-year-old as possessing “a twinkle in his eye” and the ability to “light up a room”. Confident and optimistic, Mr King never wastes time “worrying about things that are irrelevant”. Work anxieties do not keep him awake. “I go to bed, close my eyes and go to sleep,” he chirrups.

So it is rather disconcerting to puncture Mr King’s legendary cheeriness. Asked what it is like to be permanently in the shadow of Tesco, Britain’s biggest supermarket chain by market share, Mr King becomes irritated. “I never think about it,” he snaps, leaning forward from a small leather sofa in the meeting room at J Sainsbury’s modern, airy headquarters – a cross between a vast airport lounge and a hypermarket – in Holborn, central London. A blue abstract painting, photos of his family and a large orange jumper that hangs on a coat-stand are the only personal touches in the otherwise bland room, which doubles as his private office.

Being number one, he asserts, is not important. Surely he must have punched the air with joy when, in December, Sainsbury overtook Asda as the UK’s second-largest supermarket by market share, recapturing a position it last held in 2003? No, he says, his focus is solely on his own company. “What is important is where we can get to in a year’s time. That is how we define success. The [outcome], if others fail or do less well, might be that we overtake them, but it’s not the purpose.”

The stocky supermarket chief, who is a keen jogger and as a child wanted to be Bobby Charlton (not for his “haircut but his football skills”), likens his strategy to that of former athlete Lord Coe who “tried to win by running faster than the other guy”.

The metaphor is baffling. After all, Lord Coe, now the chairman of the London Organising Committee for the London 2012 Olympic Games, which Sainsbury sponsors, wanted to beat his competitors and win a gold medal. “When I say our success does not require anybody else’s failure, I really mean that,” he insists.

That is not to say, Mr King concedes, that he does not monitor his rivals and occasionally copy their best ideas. “You cannot have a monopoly on great ideas,” he says. “So make sure you spot your competitors’ when they have them, interpret them for your business and your customers and your colleagues. But don’t be frightened of taking other people’s ideas and doing them better.”

His strategy has worked. Since being brought in as chief executive from Marks and Spencer in 2004, he has turned round a supermarket that was in decline. On his appointment, employees told him they wanted to stop pretending they had jobs elsewhere and could be proud to say they worked at Sainsbury. His commitment to quality food, ensuring shelves are fully stocked with items customers want, as well as strong marketing, notably advertising campaigns fronted by television chef Jamie Oliver, has revived the group. It has enjoyed consistent sales growth for the past six years.

Sainsbury’s buoyancy has confounded doom-mongers who prophesied the recession would see the mid-price supermarket lose customers to discount retailers such as Aldi and Lidl. It didn’t. Mr King says the thesis missed two key points: Sainsbury’s transformation and that shoppers would stay true to their values, refusing to compromise on quality food, such as meat from animals raised to high welfare standards, in spite of the pressure on their finances.

Nonetheless, Mr King, who sits on the government’s business advisory group, does not want to play down the continued difficulties facing consumers. “They are huge and accelerating, not decelerating.” With the rising price of petrol, the recent increase to value added tax and the prospect of public sector job losses, further tax rises and spending cuts. “It is only going to get worse,” he says.

But some analysts are concerned that profit growth has not been as spectacular as Sainsbury’s sales acceleration. Its operating margin is a little more than half that of Tesco’s. Sainsbury is expanding its store estate aggressively, and there is a question mark over the returns this will generate – particularly as Tesco is equally zealous. Sainsbury has also suffered a setback in its ambitions in non-food, with the departures, late last year, of its directors of clothing and general merchandise, while its convenience store roll-out is behind schedule.

And Sainsbury has yet to develop an overseas operation – unlike Tesco, which has a powerful international presence spanning central Europe, Asia and a nascent US business. Mr King will not be drawn on his plans, aside from saying: “At the moment, going international is neither necessary nor desirable.”

A child of the 1970s, Mr King was raised in Solihull, in the West Midlands, by a stay-at-home mother and a petrochemical salesman father, from whom Mr King clearly inherited the gift of the gab and a pragmatic approach to money. “If you wanted a bike, you went and earned the money to have one.”

He studied business at the University of Bath and was destined to work for his sponsor, Lucas Electrical, then the UK’s biggest component supplier to the motor industry. But he changed his mind when he realised it was a company “on the slide”. “I said: ‘Well, I’d like to be running [it] in 20 years’ time but [it won’t] exist in 20 years’ time. So I’ll have to go elsewhere.’”

After graduation he joined Mars, the confectioner and breeding ground of many senior British bosses. “It was a fantastic training school; you were given opportunities very early that you would have spent years building up to in other organisations.” After spells at PepsiCo and Häagen-Dazs, he joined Asda. A company man, he never harboured any desire to set up his own business. “If you can be an agent for change in a big organisation it’s a much greater challenge than creating something yourself.”

One of his earliest jobs at Mars, selling chocolate to corner shops in east London, taught him an important lesson: key to understanding a company is knowing what goes on at the front line. He describes his approach as “top and bottom management” – “I’m managing a board, they’re empowered to get on with running the business. But I also make sure I stay very close to the coalface” by making visits to suppliers and stores.

Mr Norman, now chairman of ITV, the UK broadcaster, identifies this quality as integral to his protégé’s transformation of the business. “He really knows his company [and pays] attention to detail. People at Sainsbury feel his arm on their shoulder.”

Mr King encourages employees to talk to him. “It’s one of the ironies of leadership that people don’t willingly equip you with the knowledge to make great decisions,” he says. “And yet they expect you to make great decisions and think you’re an imbecile if you don’t.” Not shooting messengers is a guiding principle, because, if you do “they stop coming”.

He views family holidays as an opportunity to reflect on Sainsbury’s performance and goals. Isn’t that incredibly unrelaxing? “Oh no, I can do that in a very relaxing way ... in shorts, unshaven, while jumping on an [inflatable] banana.”

With a lot of change at the top of Britain’s big four supermarkets, Mr King looks set to take on the role of industry grandee. Sir Terry Leahy will step down as chief executive of Tesco at the end of February. Andy Bond left Asda in April, while Marc Bolland defected from Wm Morrison to lead M&S, thereby making Mr King the longest-serving chief of the big four supermarkets. “I don’t think of myself, and I hope I never do, as the grandee,” the boyish-looking chief executive insists.

But with so many departing executives, attention has turned to whether Mr King will be next to hang up his grocer’s apron. “Do I look like someone who’s not enjoying the job that I’m doing?” he says, his white teeth flashing.

Copyright The Financial Times Limited 2018. All rights reserved.

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