The founder of the World Wide Web has called on Facebook to ban political adverts.
Sir Tim Berners-Lee also accused the Conservative Party of spreading misinformation ahead of the upcoming general election.
He warned of a “digital dystopia” as he launched a global action plan aimed at tackling misuse of the web.
Sir Tim made a personal appeal to Facebook founder Mark Zuckerberg to ban targeted political adverts on the platform, amid concerns it is a threat to the general election.
He told the BBC: "It's not fair to risk democracy by allowing all these very subtle manipulations with targeted ads which promote completely false ideas.
“They do it just before the election, and then disappear."
Sir Tim said the renaming of a Conservative Party Twitter account during a live TV leaders’ debate last Tuesday was “impersonation”.
The Tory press office account @CCHQ was rebranded as “factcheckuk” during the debate, which saw Boris Johnson and Labour’s Jeremy Corbyn go head to head on ITV.
Sir Tim said: "That was really brazen.
"It was unbelievable they would do that. Don’t do that. Don’t trust people who do that.
"What the Conservative Party has done is obviously a no-no. That's amazingly blatant.”
After the rebranding, foreign secretary Dominic Raab said “no one gives a toss” about misleading the public on Twitter.
The Conservatives claim it was always clear the rebranded account belonged to the party.
Sir Tim is unveiling a series of standards in Berlin on Monday over fears of election interference, harassment, invasion of privacy and the spread of disinformation.
His World Wide Web Foundation has put together a Contract For The Web, calling on governments, companies and the public to ensure the web is a safe, free and open platform for all.
The commitment has been backed by hundreds of organisations, including Google and Facebook, which sets out nine key principles.
“The power of the web to transform people’s lives, enrich society and reduce inequality is one of the defining opportunities of our time,” said Sir Tim.
“But if we don’t act now, and act together, to prevent the web being misused by those who want to exploit, divide and undermine, we are at risk of squandering that potential.
“The Contract For The Web gives us a roadmap to build a better web. But it will not happen unless we all commit to the challenge.
“Governments need to strengthen laws and regulations for the digital age. Companies must do more to ensure pursuit of profit is not at the expense of human rights and democracy.
“And citizens must hold those in power accountable, demand their digital rights be respected and help foster healthy conversation online. It’s up to all of us to fight for the web we want.”