Donald Trump was endorsed for President by Denzel Washington, Robert De Niro and the Pope. The new leader of the Free World was born in Pakistan and described Republican voters as “the dumbest group of voters in the country”. Hillary Clinton employed a body double to make public appearances during the election campaign, sold arms to Isis and has been indicted for treason.

None of these stories is true, but all of them have been widely shared on social media – often by people who sincerely believed them.

An analysis carried out by BuzzFeed found that “fake news” generated more engagement on Facebook than real news stories in the three months leading up to the US election. It found that the 20 top performing false stories about the US election generated 8.71m shares, reactions and comments on Facebook. Over the same period, the equivalent figure for the 20 top stories from major news publishers was 7.36m.

“Fake news” may not have swung the US election, but few dispute it helped convince many voters they were right to support their candidate by providing the supporting evidence they were searching for to legitimise their choice. That cannot be healthy for democracies, which operate on the assumption that voters make choices based on facts and information that are for the most part accurate and truthful.

Edward Snowden addresses Facebook fake news claims

That is one reason we place such a high value on a robust and independent press and broadcasters free from state interference or control. Facts may be fiercely disputed or interpreted in dramatically different ways – and occasionally they may even turn out to be wrong – but as long as they are scrutinised and interrogated by journalists, they rarely survive long without being exposed as false. Until now.

The way news is disseminated and consumed has changed dramatically. Fake or highly unreliable news stores are manufactured by partisan protagonists, or those who are out to make a quick buck, and distributed on social media, including Facebook and Twitter, now the primary source of news for many people.

We all read the news stories, facts, quotes and information shared by friends, or friends of friends, on social media – many of whom share our view of the world. So when we glance at our feeds we see our own prejudices and assumptions reflected back at us. Twitter can become an echo chamber. Facebook can paint a picture of the world as we would like to see it rather than as it actually exists. We can end up seeing only news which is partisan, untrue and difficult to challenge.

It can be tempting to share a meme showing “what the mainstream media won’t tell you”, but somtimes the much-derided “MSM” won’t tell you something because it checked it out and it wasn’t true. That's why we need good journalists and good journalism.

As shadow secretary of state for culture, media and sport, I want the Labour Party to engage with this issue. I have asked the Government, in written parliamentary questions, about the implications of trends in the sharing of fake news on social media.

Labour will also set up an inquiry into fake news that will seek to understand the problem and make recommendations about how the phenomenon can be better understood and managed.

The decision of both Google and Facebook to try to stop “fake news” sites from using their advertising networks seems like a step in the right direction. But perhaps in future, the “news” produced by websites set up solely to churn out propaganda could be flagged as potentially inaccurate, in the same way that emails containing spam come with a health warning.

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The inquiry will ask if social media platforms could, or should, take steps to ensure users are exposed to a greater diversity of views, and whether they have a responsibility to prevent fabricated content being widely shared. It will explore whether they can make editorial decisions without being accused of political bias. The questions are complicated – but they need to be asked.

I don't want to sound too gloomy about the business of news or the future of political discourse in the UK and elsewhere. Social media platforms could help create a code of ethics for sharing news. It could be that all of us develop a habit for wading through lies and misinformation so that fact-checking becomes second nature. Perhaps it will even encourage us to pay for information produced by reputable news sites? We could even see the emergence of online communities that check news in the same way facts are checked, challenged and changed collectively on Wikipedia.

I've never been afraid to take on the mainstream media when it abuses its power or acts illegally or unethically – by hacking phones, bribing public officials or going through people's bins. And complaints about the “biased MSM” are sometimes justified. But the solution does not lie in the creation of a form of pseudo-journalism that is even more biased, less rigorous and often based on downright lies.

We all want a strong press in this country, even if I happen to disagree with many newspapers a lot of the time. The practical, political and ethical questions raised by fake news are complicated. But for the good of our democracy, we all need to start engaging with them.