Sir Tim Berners-Lee speaks at the Web We Want Festival at the Southbank Centre in London

The inventor of the world wide web said he is fighting a growing battle to keep the internet out of the hands of powerful people who threaten its freedom.

Sir Tim Berners-Lee said he is up against "big companies" who want to tweak the laws to have "tremendous" control over the lives of web users.

The internet has come under increasing scrutiny surrounding privacy and censorship following revelations of data gathering by Government security services across the world and the EU's decision to allow individuals to ask search engines to remove links to information about them.

But he denied that his creation, now 25 years old, has been tainted by ever evolving obstacles, from spying to child pornography, describing it as a "neutral platform" which reflects all aspects of humanity.

The London-born computer scientist, aged 59, has been marking the quarter century of the revolution he started by campaigning for an online "Magna Carta" of rules which would enshrine the independence of the internet and the privacy of its users.

"It (the web) has got so big that if a company can control your access to the internet, if they can control which websites they go to, then they have tremendous control over your life," he said.

"If they can spy on what you're doing they can understand a huge amount about you and similarly if a Government can block you going to, for example, the opposition's political pages, then they can give you a blinkered view of reality to keep themselves in power and if they can spy on you and find out the people who are really serious dissidents then they can round you up and put you in jail.

"So suddenly the power to abuse the open internet has become so tempting both for government and big companies.

"There have been lots of times that it has been abused so now the Magna Carta is about saying everybody using the web take this year to stand up and say I want a web where I'm not spied on, where there's no censorship.

"Generally everybody feels like that openness is really important, the only people who are pushing back are the lawyers in the big companies who realise that if they can make a play to take over control, that it will be so valuable that it's worth them spending a lot of money trying to tweak the laws to allow loopholes which will allow them to start abusing people."

Sir Tim attended the first day of the Web We Want Festival at London's Southbank Centre this weekend, a partnership between the arts centre in central London and Sir Tim's World Wide Web Foundation, which is encouraging all web users to think about how they want the internet to develop.

He added that it was an "important principle" that the web was able to reflect all of humanity, despite it enabling a "ghastly" side to exist.

"If I designed a web where you can only put nice things on it then you would have to be some central office of niceness where you would have to ask permission to put stuff up," he said.

"When you have something that is a neutral medium the web is not censoring what is going on then you're looking at humanity, you're looking at a mirror of humanity. You see some wonderful stuff and you see some ghastly stuff.

"That's an important principle that it can mirror humanity.

"Now some things are of course just illegal, child pornography, fraud, telling someone how to rob a bank, that's illegal before the web and it's illegal after the web."