The inventor of the world wide web has warned that "a growing tide of surveillance and censorship" threatens the future of democracy, as more people now use the internet and social media to "expose wrongdoing".

Sir Tim Berners-Lee, who launched the web on Christmas Day 1990, said some governments were "threatened" by this, and said "bold steps" were needed.

Speaking ahead of an event where a global league table classifying countries that put the web to work best was announced, the 58-year-old computer scientist said: "One of the most encouraging findings of this year's Web Index is how the web and social media are increasingly spurring people to organise, take action and try to expose wrongdoing in every region of the world.

"But some governments are threatened by this, and a growing tide of surveillance and censorship now threatens the future of democracy.

"Bold steps are needed now to protect our fundamental rights to privacy and freedom of opinion and association online."

Sweden topped the Web Index league table launched by the World Wide Web Foundation, followed by Norway in second, the UK in third and the US in fourth. Web innovators, experts and policymakers were gathering in London to assess the World Wide Web Foundation's independent annual measure of the web's impact.

The UK, despite falling down on privacy rights, was propelled by its high scores on availability of relevant content and political impact.

The Index revealed also that the world faces a growing participation divide, as unequal access to knowledge and speech online denies millions the necessary tools for free and informed participation in democracy.