Metal Michelangelo

"I have a hatred of the paper involved in all these jobs," he confesses. "And I won't have a computer in the office. I build the complex jobs in my head."

A 6 ft 4 inch giant with the beard of a gnome, Tustin is managing director of Littlehampton Welding, a South Coast steel and architectural metalwork contractor that bashes steel and aluminium for the architectural elite. His portfolio includes the London Eye, the wonky-columned Peckham Library and the floating bridge at London's Canary Wharf.

The more difficult the job, the more Tustin relishes it: "I'm not interested in competing for pedestrian crossing railings. There's plenty of other firms that'll do that. I enjoy helping the designers of this world solve their problems."

Architects and engineers rate the maverick metalworker as one of the most outstanding fabricators in the country, and speak of him with real affection. "I adore him," says Amanda Levete of Future Systems, which uses Tustin on almost every job it does. "He's somebody you're immediately drawn to as a person. He's incredibly knowledgeable and a very instinctive character. He's a real problem solver; there's nothing that's too small or too complicated."

"A lot of people are scared of doing difficult things, but not Bill," adds Hanif Kara of Adams Kara Taylor, engineer on the award-winning Peckham Library. "He's always smiling and joking – nothing is a problem to him. If you have a doubt about something he makes, you feel silly for feeling that way. He's a man of his word who delivers what he promises."

Tustin's renegade tendencies were apparent from an early age. After being expelled from school for "being too much of an individualist", he got a job on a farm working with cows and polishing the farmer's Jaguar.

He then got a job as a piece-worker at a light engineering firm, where he learned the metal trade making chimneys, pressure vessels and watertanks. He joined what would become Littlehampton Welding in the early 1970s when it was still a "very small, very disorganised" firm. In the recession of 1982, a string of clients went out of business and the firm was forced into receivership. Tustin seized his chance. With a colleague, he bought the firm from the receiver: "From that moment on, we never stopped making money."

I’m not completely convinced of the merits of CAD drawings. The quality of details has reduced and it’s no quicker

Tustin, 54, is as gifted a businessman as he is a craftsman. He now employs more than 100 people and turns over about £8m a year. He spends his mornings at home, mentally pricing jobs, and the accuracy of his quotations is legendary. "The way we quote a job is to get inside it. The only way to get the price right is to build the job in your head."

The apparent chaos of his office is the product of an unorthodox, but seemingly effective, approach to document management. Referring to a story he once saw in a magazine, he dives into the paper river and immediately pulls out the edition. Later, in what passes for a spot of filing, he slings a bundle of papers across the room, where they come to rest on another heap beneath a desk.

His laugh is a Sid James-cackle and his language is as colourful as a pantomime pirate. "If you write that I'll come up to London and slit your throat," he jokes, after the mildest of indiscretions. "I'll have your guts for garters if you put that in," he says after another.

We leave the office and head for the shop floor, where Tustin banters with his staff and lovingly shows off his new shot-blasting machine. "Iron-fighting is a fair description of what we do," he says, as we walk past a team of welders assembling a giant spiral staircase for Foster and Partners' Tag McLaren headquarters. "It's a question of big hammers and lots of heat. With steel, especially stainless, everything you do is a challenge. There's always an element of the unknown. You put two bits together and you can't always tell exactly what it's going to do."

Littlehampton Welding is rooted in the crafts tradition and Tustin comes across as slightly old-fashioned. The firm uses computer-aided design wherever possible, but Tustin is sceptical about its merits. "Everything we do is a one-off. Other firms just whack everything into a machine, but we don't do that – we're very much hands-on. And I'm not completely convinced of the merits of CAD drawings. The quality of details has reduced and it's no quicker."

He is happiest working directly with the most demanding architects, interpreting their detailed drawings and figuring out how to realise their ideas. He's not so keen on designers that don't really know what they want. "We get used as an architect's detailing office, which is totally ridiculous. Clients are beating down the architects on fees and that's passed the need to draw things further down the line to us."

This is followed by a minor rant about construction management, which gets in the way of his direct contact with designers and slows down decision-making. The trust has gone, he says, and "it frustrates terribly".