World Wide Web founder Sir Tim Berners-Lee has warned that the internet's power for good is being "subverted" by those spreading hatred and threatening democracy, as the technology marked its 50th birthday.

Sir Tim urged governments, campaign groups and individuals to back a new plan from his foundation to make the internet safe, fair and accessible to all.

The computer scientist spoke out on the 50th anniversary of the University of California, Los Angeles (UCLA) professor Len Kleinrock sending the first message on the Arpanet network of computers, which would eventually become the internet.

Twenty years later, Sir Tim created the World Wide Web – first proposed as an information management system while he was working for the European Organisation for Nuclear Research (Cern) – which led to the mainstream establishment of the technology.

"It's astonishing to think the internet is already half a century old. But its birthday is not altogether a happy one," he said.