HE is going but not gone yet. Anthony Bolton is still very much in the building at Fidelity International – and plans to be there for some time.

“It’s a change of job. I am not retiring,” says Bolton. “I am just taking on a less pressurised role. And a key part is passing on what I have learnt to the team.”

Understandably there are jitters at Fidelity, one of Britain’s biggest investors, that next month’s exit of their star fund manager will see a rapid removal of money from their accounts. Bolton has run the Fidelity Special Situations fund since 1979 and proved himself probably the best stock picker in London. Over 28 years his fund, one of the City’s largest, has had an annualised growth rate of 19.7% (against 13.8% from the market).

More than that, he has provided a compass-like base around which much of corporate Britain has revolved. As part of Fidelity’s top tier, he sees the senior teams of two or three different companies a day, on average, for presentations and questions.

They troop to Fidelity’s base opposite St Paul’s Cathedral in the hope of getting his investment and, by implication, his approval. That’s why he is regularly cited as one of the most influential men in the City.

Mostly, he has wielded that influence discreetly. But just occasionally, as when he prevented Michael Green from becoming chairman of ITV in 2003, Bolton has waded in and told management how things should be done. He has not quite forgiven this newspaper for dubbing him The Quiet Assassin on that one.

“Actually I think I have got over it,” he says drily. “I just felt it wasn’t true. It very much personalised a Fidelity situation rather than an Anthony Bolton situation, and assassin is such an emotive word.” Such forensic analysis is a Bolton trademark, as is a love of anonymity. Sitting in a vast meeting room by Fidelity’s front door – which is as far as the firm likes to let visitors go – he looks more like a senior civil servant than a hitman.

Aged 57, plain suited, slight and bald, with a long, pale face framed by tufts of white hair, he has only one distinguishing feature: a signet ring and wedding ring worn side-by-side on his little finger. You see a lot of them as he conducts his listening, and his talking, with chin in palm. The ringed finger taps his cheek in time with his impatience.

Or perhaps it is just a tune he is playing in his head – Bolton relaxes by composing classical music. He has a house in Antigua, and a home in Sussex and does much of his brain-work commuting to London by train. Despite the many millions he must have made, he has a resolutely unflashy lifestyle.

But he parts with these details sparingly. Profile, in his line of work, is not an asset. Or as he says in Boltonspeak: “I wouldn’t high-light it as useful”.

And now it all stops. So why is he stepping sideways? “I am getting out because it is a very intensive business, and it gets more intensive, more difficult, more competitive with more investments. It’s a nil-sum game.”

And the way he works, soaking up huge amounts of data topped up with meetings – he has 52 notebooks upstairs in his office, detailing every encounter – means he has had enough. Close to burn-out?

“The stock market is there, day in, day out, and you have to take in lots of information, and I have got to the stage where I want to turn that off and do a few other things.”

But such has been his success that leaving was never going to be easy. Bolton’s contrarian streak and above-average returns have earned him renown in fund-management circles. How does he manage the disappointment of Fidelity customers who invested in him to make their money grow?

He thought he could mitigate that by announcing his intention to quit two years ago, and then passing on control of his fund slowly – first splitting it in two, handing over one half last year, and the rest next month.

“I’ve had a lot of criticism for this,” sighs Bolton, “but I like planning and doing things in a methodical way and I thought if I turned up one day and just said ‘sorry folks, that’s it, someone else takes over on Monday’, that would be leaving people in the lurch. What I underestimated was how much firepower that has given to the competition to say ‘look, he is on the way out’.”

He grimaces then redraws his poker face. Even those who have known him for decades find him a hard man to call.

But tales of Bolton’s acuity are legion. His Special Situations fund – so named because it likes to take risks – often backs smaller companies, turnaround or recovery stocks. Bolton is also good at seeing potential where others see little.

He bought Nokia, the Finnish timber and phone firm, before it switched its focus to telecommunications. He held Man Group long before hedge funds became fashionable.

More recently he has looked less certain – advising this year that he thought a share slump was imminent. “I was cautious. It was a time when people were being too optimistic. My view is that the environment will be tough for a while, some of the banks will need more equity, but out of this will come a great opportunity next year for shares.”

Which ones? He smiles. “A whole cross-section, including financial shares.”

Part of his skill is judging not just businesses but managers. He credits British management with being far more responsive than when he started. “Managers are more incentivised on what shareholders want.And they are younger. The average tenure for a chief executive is three years, isn’t it? There are not many Sir Martin Sorrells around.”

Bolton has been a significant backer of WPP – which Sorrell founded – since the mid1990s. Sorrell himself is a confirmed Bolton admirer. “Anthony has quietly built a very successful, powerful and wise brand,” says the WPP chief executive. “He is one of the most astute investors I have come across.”

Peter Hargreaves, veteran boss of the brokerage Hargreaves Lansdown, is another fan. “Many fund managers are not good judges of character, but he is,” says Hargreaves. “His asset is his detachment. He does not really want to tell you anything.”

Unless, that is, he and his team feel you could do better. Bolton explains: “We don’t go into companies trying to change them, but if we think they are not developing as well as they might, we have two options – sell the shares or try to influence them.

“Five years ago I started a team to concentrate on trying to influence them. If you are a big investor you can have influence. And changing strategy, or the management team, is something you can get involved in.”

That is a style he has developed working his way through the City. Brought up in London, the son of a barrister, conventionally educated at Stowe and Cambridge, Bolton was trained as an engineer but entered banking after a nudge from a family friend.

He started at Keyser Ullman, a small merchant bank that later sank in the secondary banking crisis of the mid1970s. By then, Bolton had joined the London outpost of Schlesinger, a South African fund manager. When one of his bosses jumped to join Fidelity, a privately-owned American fund firm that was launching in Europe, Bolton jumped too.

At Fidelity he grew with the business, developing his methodology with an engineer’s quantative skills – highly research-driven, charting historic trends, scouring for hidden value. To win big, he moved frequently against market sentiment.

Bolton has had rough patches: three poor years to 1991 in particular. Bad investments like Polly Peck, Parkfield and Mountleigh taught him the value of balance-sheet analysis, and to be wary of bosses’ promises.

But Fidelity has always backed him. He went on to run many funds, controlling £10 billion of investments as if it was nothing more complex than chess. And he relished the pressure, according to colleagues.

“Anthony has this calm objectivity,” says Alexander Scurlock, who took over Bolton’s Fidelity European Growth fund. “He is not emotional about market fluctuations. When he senses the market moving, his question is: how can I get on the other side?”

That ability to foresee trends will still be available to Fidelity International, which has £148 billion under management. In his new role, Bolton will be “a resource”, happy to advise all the company’s fund managers.

He will also have a special project: bringing his analytical skills to bear on charities so he can advise Fidelity clients which of them make the best use of their money. Some charities, you would have thought, will not be welcoming the assassin’s assessment.

Bolton is phlegmatic. “I would like to think that people would still want money to go to the best in class, rather than the worst in class.”

Does he believe, looking back, that he has achieved something worthwhile – more than just pushing money around?

He doesn’t bristle, just nods. “Um, I do. A kind competitor said to me today ‘Anthony, you’ve probably made more money for investors in this country than anyone else’. That’s the motivation.”

I bet the competition is glad he is going. Bolton taps his cheek in thought. “I am very aware this is very transitory. People will forget me pretty quickly.” Really? I wouldn’t be so sure about that.

ANTHONY BOLTON’S WORKING DAY

BRITAIN’s most successful fund manager wakes at his home outside Midhurst, West Sussex, at 6am. Just 45 minutes later, Anthony Bolton is on the train to London, reading research. “It’s a key time. I prepare for the day.”

He arrives at Fidelity’s City office by 8am. His day is then full of back-to-back appointments – analysts, fund managers, companies and brokers. He rarely eats out, preferring in-house breakfasts and lunches.

At 6pm he leaves, and works methodically through more research on the train. “I get a pile of paper a foot high every day. I am home at 7.30 and in bed by 10.30. I need a reasonable amount of sleep,” he says.

VITAL STATISTICS

Born:March 7, 1950

Marital status:married, with three children

School:Stowe

University:Trinity College, Cambridge

First job:trainee, Keyser Ullman

Salary package:undisclosed

Homes:Midhurst, West Sussex, and Antigua

Car:blue Toyota Rav

Favourite book:Man and Camel, by Mark Strand

Favourite music:The Sacrifice, by James MacMillan

Film:The Life of David Gale, a story about a man who is dedicated to the abolition of the death penalty and is sentenced to death for murder

Favourite gadget:Blackberry

Last holiday:China

DOWNTIME

ANTHONY BOLTON relaxes by writing music. “I am very influenced by Benjamin Britten, and I am lucky to have got advice and lessons from modern composers. I wrote an anthem recently for my daughter’s wedding.” He plans to spend more time composing, using the Sibelius application on his laptop, while commuting into work.

He loves to travel, especially to his holiday home in Antigua, where he can switch off from the stock market. “My parents had a house in Jamaica – my father liked it so much, he nearly emigrated – so I’ve got the Caribbean in my blood. We’ve been going for the best part of 30 years.”