After launching his party’s election manifesto yesterday, Jeremy Corbyn took questions from the press. First up was a reporter from the Morning Star, Britain’s daily communist newspaper, who asked if “anything [could] be done about the shockingly biased media?” Meanwhile an activist, dotted in Labour Party campaign stickers, was seen holding up a sign reading “Fake News” while standing behind the BBC’s political editor, Laura Kuenssberg.

If Labour Party activists feel under siege, it is understandable. Britain’s biggest newspapers lean towards the Conservative Party. An army of new and enthusiastic recruits, inspired to join by Labour’s new leader, are venturing into swing constituencies only to be told by local activists that they ought to avoid mentioning Mr Corbyn on the doorstep because of his toxic personal approval ratings. On finding that the public doesn’t share their love of He Who Cannot Be Named, many point the finger at the “mainstream media”. According to Tom Mills, a Labour-supporting sociologist, “there’s no doubt the mainstream media in the UK are hostile to egalitarian parties and movements”. The broadcasters, he says, are “overwhelmingly orientated towards elite sources in their reporting and are also influenced by the press, and so that skews their coverage against Corbyn and his supporters”.

In this belief, Labour’s sympathisers have circled the wagons and increasingly share articles and memes from a new generation of partisan blogs such as Another Angry Voice, the Canary, Evolve Politics and Skwawkbox. These sites are amateurish but command impressive followings on Facebook. They are also as politically predictable as the right-wing press. Recent headlines at the Canary include “Even BBC reporters were left stunned by yesterday’s pro-Corbyn crowds in West Yorkshire” and “There’s a quiet revolution brewing in rural England. And Theresa May should be very worried”. Their primary target is not always the Conservatives, as they seem to have just as much fun implying an institutional bias at the BBC. After Labour’s manifesto launch, the Canary ran an article titled “Laura Kuenssberg’s response to the Labour manifesto shows the BBC is moving from bias to naked self-interest”.

Anybody growing tired of Britain’s partisan newspapers might welcome a little more plurality. But unlike the headlines published in the tabloids, posts from the pro-Corbyn blogosphere seldom escape the digital universe of Labour Party supporters. Across the country, like-minded sympathisers are decorating each other’s Facebook news-feeds with enough Corbynite articles and memes to make a Tory victory on the 8th June seem impossible. The Facebook pages for Theresa May and her Tory party are dwarfed in size by those of Jeremy Corbyn and Labour.

But there are two problems for Labour. First, the Tories may get fewer “likes”, but they are quietly using big data sets to serve ads to swing voters in target constituencies—and they are the voters who decide elections. During the previous general-election campaign in 2015, the Conservatives paid Facebook over £1m to put their posts in front of ordinary voters who might not have “followed” or “liked” political parties or blogs.

Second, an increasingly fervent activist base could make it harder for Labour to broaden its appeal. In the event of a leadership contest following its expected electoral defeat next month, a more hardline party membership could reject candidates seeking to regain the centre ground. If it is to pick itself up, Labour will have to get its message beyond the online echo-chamber.