The principles of openness and universal access that underpinned the creation of the internet three decades ago are under greater threat than ever, according to Google co-founder Sergey Brin.

In an interview with the Guardian, Brin warned there were "very powerful forces that have lined up against the open internet on all sides and around the world". "I am more worried than I have been in the past," he said. "It's scary."

The threat to the freedom of the internet comes, he claims, from a combination of governments increasingly trying to control access and communication by their citizens, the entertainment industry's attempts to crack down on piracy, and the rise of "restrictive" walled gardens such as Facebook and Apple, which tightly control what software can be released on their platforms.