Inside the Web community, he is acknowledged as one of the most influential people of our day. Last month, the Massachusetts Institute of Technology appointed him to the new 3Com chair at the MIT Laboratory for Computer Science, the first-ever MIT chair for researchers rather than existing professors. Time magazine put him on its list of the "100 People of the Century", alongside the likes of Albert Einstein and the Wright brothers. "If this were a traditional science, Berners-Lee would win a Nobel prize," Eric Schmidt, CEO of Novell, once told The New York Times. "What he's done is that significant."
It all started 10 years ago at the Cern European Laboratory for Particle Physics in Geneva, where Berners-Lee was working as a software engineer. For years he had toyed with a program he'd written that represented information in a brain-like way, linking words to related documents on his computer.
In 1989, he proposed a point-and-click hypertext editor called World WideWeb that would link documents across the Internet, allowing people to share their knowledge. Given the go-ahead by Cern, during 1990 he developed a system that gave each Web page a unique address, now known as a URL (universal resource locator). He wrote HTML (hypertext markup language), the coding that embeds coloured, underlined links in text, and created HTTP (hypertext transfer protocol), the set of rules which allows documents to be linked across the Internet. In the summer of 1991, he released the program, along with the first Web server, to the public - and the World Wide Web was born.
Since then, Berners-Lee has taken on the role of Web promoter, protector and adjudicator - a kind of Yoda for cyberspace. From 1991 to 1993, he continued working on the design of the web from Cern, co-ordinating feedback from users and refining his specifications. In 1994, just as corporations and profit-seekers were beginning to see the commercial potential of the Web, Berners-Lee headed to Boston, where he joined the Laboratory for Computer Science at MIT and took on the directorship of the World Wide Web Consortium (W3C), the organisation that develops and promotes common specifications for the web.
While others have made millions from the Web, he has fought to keep his baby a non-proprietary system that is free, open and global. It means that no single company dominates Web browsers or programming languages the way that Microsoft Windows dominates operating systems. And consumers know that when they invest in products whose specifications the W3C hasn't endorsed, and create websites that recommend pages are "best viewed with", they may be digging themselves into a hole.
Berners-Lee works from W3C's US headquarters in Technology Square, a sparse, nondescript office park on the edge of the MIT campus. There's little in his smallish office to suggest his position: a whiteboard with equations scribbled on it, an empty hat stand, tacked-up posters, piles of books and papers - it's no flash corner office. Given the opportunities that he's had to make millions from his invention (Marc Andreessen, who helped develop the first popular Web browser, Mosaic, went on to co-found Netscape and became one of the Web's first millionaires), his decision to stay in research seems remarkable.
The W3C press office protects Berners-Lee fiercely. In a pre-interview, the head of PR points me to a long list of answers to questions he is tired of answering, plus questions he would rather not be asked at all. He won't, for example, go into detail about his personal life. His home page lists a few carefully selected details: that he was born in London in 1955, educated at Emanuel School and Queen's College, Oxford, receiving a first with honours in physics in 1976; that his parents, both mathematicians, met while working on the first commercial computer, the Ferranti Mark I; that he built his first computer at Oxford, with a soldering iron, TTL gates, an M6800 processor and an old television; that he worked as a software engineer for various UK companies before arriving at Cern.
In person, however, Berners-Lee is surprisingly approachable. He is self- deprecatory, acknowledging an element of luck in his invention of the Web: "It was something about being in the right place at the right time with a good idea." He says he found the Time article "embarrassing, mainly because there were so many serious thinkers, especially around here [MIT]", and also because of the way it ranked people. "I have a strong feeling that everybody in the world is equally valuable and equally worth celebrating."
His look is casual (polo shirt, khakis, unbrushed blond hair), and he talks quickly and intensely, linking to related ideas mid-answer, then looping back to the main point. He can be idealistic ("The Web is a tremendous grassroots revolution. All these people coming from very different directions achieved a change. There's a tremendous message of hope for humanity in that."), yet there is nothing of the dotty professor about him. He is careful to define his terms, and avoids complicated technical jargon. Ideas pour out fully formed and illustrated with examples.
His accent is hard to pin down: you can hear Switzerland and America in there, layered over BBC English. He has lived abroad for many years, but Britain - and the state of the Web in Britain - is on his mind. Last Christmas, he found it difficult to buy presents online for his family in England. His parents don't have a connection to the Web in their home. Why doesn't Britain - which doesn't suffer the language barrier of non- English-speaking countries - have a more significant presence on the Web? He points to the example set by the US government, which originally funded the Internet. The British Government needs to "get out there and fund research". Britain should aim to get a permanent Internet connection into every home within the next two years.
"It will have a huge economic effect on how Britain is competitive, and on how educated and aware children are, and whether they can get jobs elsewhere in the world," he says forcefully. "So do it."
One way the Government can promote this is by making sure that direct Internet connections are reasonably priced, so that the public can move beyond expensive local phone calls. Telecom companies tend to lease wires into homes as if they are carrying phone calls, which take up much more bandwidth than Internet packets; other kinds of companies may be better placed to use these wires. Valuing these wires, he says "is a political problem", and the Government needs to ensure those values are determined "realistically".
Another area where he is keen to see the Government take a lead is in allowing the use of cryptography to protect computer data. To date, the UK has gone along with the US policy of not allowing strong cryptography because it hinders law enforcement - a tenuous argument that prevents online collaboration (because you need good encryption to ascertain who is participating in the group) and also means that companies have to invest money and time to create different versions of commercial products for different countries.
"E-commerce could, in fact, take off in Britain if the Government allowed strong encryption and the export of strong encryption," he argues. "We need to encourage the British Government to be part of the free world and not have their arm twisted by the FBI into forbidding cryptography."
As the Web grows in Britain, he says, it will be important to avoid two scenarios: one in which it becomes "a homogeneous monoculture of McDonald's- lands", and the other in which people dig "potholes of culture" for themselves by only visiting their favourite websites and filtering out mail from anybody who doesn't share their beliefs.
"Both are frightening, both are threats to society. We avoid them if, as human beings, we spread our attention between the global and the local." So, just as there are local and national newspapers, there should be "Welsh and Scottish and Yorkshire webs that preserve those cultures" as well as national and international sites. "I'm glad there is a national Web emerging. But I also would be very concerned if the culture became too isolated, too divorced from the rest of the planet."
In the secretive and fiercely competitive world of Web development, W3C is a unique organisation. It brings together representatives of more than 300 powerful computer, software, telecom and financial companies, including Microsoft, IBM and Sun Microsystems, and encourages them to share information and reach consensus on Web technologies and specifications. Interest groups and working groups develop specifications and make recommendations to the advisory committee, which votes on their proposals. Once a specification has been accepted, W3C relies on the power of its endorsement and, in large part, the press, to encourage companies to comply with the specification.
Every member has one vote on the advisory committee. Work in progress is presented for feedback. Objections are closely analysed and recorded. The decision to endorse a specification, says Berners-Lee, is never capricious. "It's made by a lot of people."
The final decision to accept or reject a recommendation, however, is made by Berners-Lee himself, who is quick to downplay his role in the process. "The Queen has a yes or no over Parliament, doesn't she?" he says with a laugh. "It's a similar sort of model."
Current W3C activities range from legal and policy questions (eg, the Platform for Privacy Preferences project, which protects individuals by letting them know what a site's privacy practices are, such as if a site is recording their browsing habits), to user information and architecture questions (eg, ensuring Web data formats integrate with mobile devices and television standards).
A hot topic around W3C these days is the development of a "Semantic Web", in which metadata - data that describes data, the way a library catalogue describes books - is encoded in Web content. "If the Web turns all the documents in the world into one big book, then the Semantic Web will turn all the databases in the world into one big database," Berners- Lee explains, thus allowing huge inter-operability: imagine if your desk- diary application could talk to everyone else's desk diary.
Berners-Lee is constantly thinking about the Web, what it can do today and where it should be in 10 and 20 years' time. "There's certainly a whole lot more we still have to do, in terms of making the Web a creative space." For example, digital cameras could relay pictures directly to a Web page. "What you want to do after a holiday is put all your pictures on a table with friends; but you can't do that with the Net."
There should be folders on the Web. Berners-Lee says we should never have to think about uploading, but only about giving others access to folders of information. And there should be a Web brand that identifies unbiased content, so that users are aware when companies have paid for links and search results.
"I grew up with the BBC painting the Fairy Liquid bottle white on Blue Peter when they showed you how to make a vase for Mother's Day because they were so frightened about product placement," he says. "We teach kids who to trust from the moment they learn to talk. We need to find ways of expressing the value of editorial independence on the Web."
What's holding back these intuitive developments, he suggests, is "a mentality that the Web is a distribution mechanism - that the creation and distribution processes are separate". People need to adopt "a different mentality where people and information are in equilibrium".
Has he ever regretted not cashing in on his creation? Certainly, he is aware of the money that former colleagues are making.
"All the commercial excitement [about the Web] means that if you have a great research group it will be difficult to hold on to them in a university, because they keep on going to start-ups and getting filthy rich," he says wryly. "But at least when they come back they're not worrying about where they get a grant from."
As Tim Berners-Lee ponders the possibilities for the World Wide Web in its second decade, sliding easily from broad cultural and political issues to the smallest details of technology and infrastructure, it is clear that he is still excited, energised and enthralled by his creation. You suspect that he would be quite bored by the day-to-day slog of mere financial gain.