Internet companies such as Google should not be responsible for censoring content, one of the web's founding fathers has said.

Vint Cerf, who is credited with inventing one of the internet's key protocols and now holds the position of chief internet evangelist at Google, said companies should comply with existing laws and take down illegal content when requested to do so, but should not actively seek out breaches.

He said that Google "felt a responsibility" when it came to content that people were accessing via its search engine, but added that the company did not have control over what users posted. Only when illegal content was brought to its attention – as has happened on YouTube, the video-sharing site owned by Google – should it be compelled to act, he said.

"I think of the internet as a road system," Mr Cerf told BBC Radio 4's Today programme. "When you invent a road system, the next thing that happens is other people invent vehicles and figure out what buildings to put on the sides of the roads. I don't have any control over that, and I don't have any responsibility for it either."

"If it's concluded that the act of putting [content] on the internet is illegal, then something could and should be done about it," he said.

Asked whether he was broadly in favour of regulating the internet, he said: "We need to be very careful about what is inhibited. Where on this slippery slope to do you draw the line?

"Most of the content on the internet is contributed by users, so what we see there is a reflection of the society we live in. Maybe it's important for us to look at that society and try to do something about it. When you have a problem [with what you see] in the mirror, you don't fix the mirror. You fix that which is reflected in the mirror."

Mr Cerf was reiterating a position frequently adopted by internet companies that they are "mere conduits" of information, and should not be responsible for illegal content posted by third parties that is accessed using their services.

Internet service providers have long said that they have no editorial control over the content on the hundreds of millions of sites they help their customers to access, arguing that they are more like a postal service.

Mr Cerf, who in the 1970's helped develop the TCP/IP protocol that enabled computers to communicate with one another, also defended Google's decision to censor its service in China to abide by the country's strict approach to online content.

"To operate in China at all, we have to follow their laws, so we suppress certain output from our search engine in accordance with those laws," he said.

Yesterday Yahoo! said that it had been merely obeying the law when it gave Chinese authorities the registration details of one its users who had been critical of the Government, and who was subsequently sentenced to ten years in prison.

Mr Cerf, who gave a talk at the Edinburgh International Television Festival at the weekend, also dismissed suggestions that the internet would spell the death of television. "I think the video medium combined with the interactive quality of the internet will help [content providers] reinvigorate what television can be," he said.

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