The web should be as free and unconstrained as a blank piece of paper, its creator has said.

Speaking at a BBC event to mark the 20th anniversary of the web, Sir Tim Berners-Lee said the internet should not be controlled, censored or intercepted by government or companies.

He asked the audience to consider someone looking up sensitive information - such as cancer symptoms or what it's like to come out as homosexual. If a government or company is monitoring every click, people won't feel comfortable using the web to find help with such matters, degrading the usefulness offered by the online world, he claimed.

"The internet should be like a white piece of paper," he said.

When you buy paper, "it does not come with the fundamental constraint on it that you can only write truth," he said, adding that you "can't get drawing paper where it's impossible to draw a nude figure."

Anonymous

That said, Berners-Lee doesn't think web users should always be anonymous. He said anonymity is important in some cases - such as when people were struggling against their government - but added that much of what was said online didn't require such protection. He said we need to "realise that the whistle blower syndrome is an emergency, it's an exception."