JON Snow, the Channel 4 News presenter, has warned that Facebook could be a "vast threat to democracy" if its role in spreading false stories goes unchecked.

Delivering this year’s MacTaggart Lecture at the Edinburgh International TV Festival, Snow said the power of Facebook means it has a "moral duty" to prioritise truth.

Snow said that the power of the platform has a “dark, cancerous” side that enables fake news to spread widely.

Snow, delivering the keynote speech at the festival, said that Facebook, with its global reach can "prioritise fakery on a massive scale."

Snow added: “That same algorithm that prioritised many amazing reports of ours, also prioritised fakery on a massive scale.

“Facebook has a moral duty to prioritise veracity over virality.

“It is fundamental to our democracy.

“Facebook’s lack of activity in this regard could prove a vast threat to democracy. Facebook’s principles are seldom explained in detail and can change over-night at Mr [Mark] Zuckerberg’s [Facebook founder] whim.”

He added: “Rather than simply trying to take down the fakery, there has to be an incentive for Facebook to pay the rate for high quality news and encourage the development of a global bedrock of truths rooted in their offer to the quarter of the world’s online audience.

“Indeed when you read Zuckerberg’s manifesto for the future he seems to think Facebook will invent and establish quality journalism. There is no need to Mr Zuckerberg.

"It already exists, independent of Facebook...now we all need to work together and find another way of supporting it - before it’s too late."

Mr Snow added of Mr Zuckerberg: "He says he cares about news, but does he really? Or does he care about keeping people on Facebook?"

Elsewhere in the speech, Mr Snow said the Grenfell Tower disaster had shaken him and made him believe the media are in breach of an obligation to “be aware of, connect with, and understand the lives, concerns and needs of those who are not” part of the elite.

He said that “in increasingly fractured Britain, we are comfortably with the elite, with little awareness, contact, or connection with those not of the elite.”

Mr Snow also took aim at Facebook and its role in providing a platform for false news stories, saying that if unchecked it could pose a “vast threat to democracy”.

In the speech Mr Snow also said that the explosion of digital and social media has not filled a hole left by the decline in local newspaper journalism.

He said: “The explosion of digital media has filled neither the void left by the decimation of the local newspaper industry - nor connected us any more effectively with ‘the left behind’, the disadvantaged, the excluded.

“Never have we been more accessible to the public nor in some ways more disconnected from the lives of others.”

Referring to the Grenfell disaster in June, he said: “Why didn’t any of us see the Grenfell action blog? Why didn’t we know? Why didn’t we have contact? Why didn’t we enable the residents of Grenfell Tower - and indeed the other hundreds of towers like it around Britain, to find pathways to talk to us and for us to expose their story?”

Snow said that after the Grenfell disaster he felt “disconnected and frustrated”.

He added: “I felt on the wrong side of the terrible divide that exists in present day society and in which we are all in this hall, major players. “We can accuse the political classes for their failures, and we do.

“But we are guilty of them ourselves.

“We are too far removed from those who lived their lives in Grenfell and who, across the country, now live on amid the combustible cladding, the lack of sprinklers, the absence of centralised fire alarms and more, revealed by the Grenfell Tower.”

Snow said that the “virtual collapse” of local journalism meant that the media becomes more dependent upon reporting what is going on “at the centre”.

He added: “Could things have turned out differently had a local reporter been aware of Eddie Daffarn and his blog at Grenfell Tower and seeped his warnings of danger and devastation out into the media mainstream before it was too late?”