Regulators should investigate the role of Google, Facebook and digital advertising in the spread of fake news, a media body has said.
The News Media Association (NMA), which represents national and local publishers, said the digital advertising supply chain which favours fake news and helps it to thrive was "murky at best, fraudulent at worst".
In a recommendation to the culture, media and sport committee's fake news inquiry, the body called for an "urgent investigation" by regulators such as Ofcom and the Competition and Markets Authority (CMA) into its impact on Google and Facebook.
Lucy Gill, legal policy and regulatory affairs adviser at the NMA, said fake news is more likely to be spread on sites such as Facebook due to an algorithm which measures stories' worth based on virality.
Fake news stories, which are more likely to go viral, also emerge more profitable than real news in terms of clicks and advertising revenue, leading the report to question the sustainability of digital news in an environment where fake news "flourishes" on popular online platforms.
She told the Press Association: "We're asking Google and Facebook to examine if what they're doing is creating a sustainable environment for real news and asking these companies to conduct meaningful reviews of the news."
The rise of "programmatic advertising", a type of targeted advertising which collects data on individual consumers from their clicks and follows them with tailored commercials, has led to adverts inadvertently appearing on fake news sites, leaving advertisers "in the dark" about how their money is spent.
The recommendations also suggest fake news "farms" deprive real news publishers of valuable advertising revenue as well as profiting because they do not incur the same costs, including paying professional journalists and in-house lawyers.
NMA chairman Ashley Highfield said: "News media publishers are by far the biggest investors in original news content, accounting for 58% of the total UK investment.
"But the digital supply chain rewards the distributors of content, not the originators. Government and regulators cannot ignore forever the impact of the Google-Facebook duopoly on our media landscape."
In its submission, the NMA suggests that UK news consumers are not as receptive to fake news as American consumers, thanks to a "robust news media sector" in Britain and string of turbulent political events in 2016, notably the Brexit vote in June, which prompted a surge in newspapers sales.
The body also criticised politicians and lobby groups who use the phrase "fake news" as a label for news they dislike, calling it a "disaster" for free speech and democracy and the fight against fraudulent news sites.
It comes days after the CMS committee boss Damian Collins hit out at Donald Trump's incorrect use of the phrase, saying the US President uses it to label news "he doesn't agree with".