Ken Livingstone has said he is worried about the role of the internet in election campaigning.
The former Labour Mayor of London said the lack of regulation online meant untruths could circulate quickly.
"Everything is happening over the internet. A big part of Jeremy's [Corbyn] dramatic increase in the vote last time was Labour focussed very much on the internet, because we're never going to get much coverage in the Daily Telegraph or the Daily Mail that's in any way positive," he told talkRADIO's Julia Hartley-Brewer.
"My worry about all this though is the internet just isn't really regulated and you can have so many lies.
"I bumped into a guy back in the summer who said 'Why did you say this?', and he spent about 20 minutes running through all the things he'd seen I'd said on the internet, and none of them were true."
His comments come after the BBC's political editor Laura Kuenssberg came under fire for falsely reporting to her 1.1 million Twitter followers that an adviser to the Health Secretary Matt Hancock had been punched by a Labour activist.
She deleted the tweet and apologised after footage emerged of the adviser walking into the arm of a cyclist, who had been protesting against the Conservative Party outside Leeds General Infirmary.
She wrote: "Happy to apologise for earlier confusion about the punch that wasn't a punch outside Leeds General - 2 sources suggested it had happened but clear from video that was wrong."
Mr Livingstone said that people were quick to believe things they saw online.
"A few days ago there was stuff on the internet saying the Queen had died. Of course people believed it initially," he added.
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