Across the top of the Daily Mail’s front page on Thursday a banner screamed: “Fake news, the fascist Left and the REAL purveyors of hatred”.

No this wasn’t another attack on Jeremy Corbyn and the Labour party, it was a full page screed against the Guardian and its criticism of the Mail’s rhetoric on Islam, which a number of commentators have suggested contributes to Islamophobia.

But leaving aside the Mail’s curiously thin skin when it comes to anyone suggesting it may have gone a bit overboard, the piece also exposes one of the newspaper’s more curious obsessions – its insistence that the Daily Mail in print has absolutely nothing to do with its website.

“Earlier this week, a Guardian writer attacked the Daily Mail for carrying comments by the controversialist Katie Hopkins. That was a lie. The Guardian and its writer know that Ms Hopkins has nothing to do with the Daily Mail but works for Mail Online – a totally separate entity that has its own publisher, its own readership, different content and a very different worldview.”

The first part of that claim is technically true. Katie Hopkins is employed directly by the website and not the newspaper. Mail Online is a separate operation (albeit housed in the same building) with separate journalists and by and large, different readers. The publisher and effectively boss of the website is Martin Clarke, not Paul Dacre (though Dacre is, at least nominally, editor-in-chief of the whole group). Clarke and Dacre do not get on.

But the claim they publish different content is rather undermined by the fact the vast majority of articles in the print newspaper end up on the website. Yes, Mail Online produces many more articles, a fair chunk of which are quickly churned out celebrity gossip, but those sit alongside stories such as this one about Prince Harry by the print newspaper’s royal correspondent, which appeared on Thursday morning’s front page, just below that banner about fake news.

If anything, the website and newspaper have been growing closer together. In 2014, Mail Online was rebranded as DailyMail.com in the US, in order to make it easier to sell digital advertising.

That’s another point remembering - the two businesses may be run separately, but they are still part of the same division of the same parent company, DMGT, which is controlled by the same person, Lord Rothermere. Both make money for the same shareholders.

All of this interconnectedness for the most part happens behind the scenes, but it does suggest the real reason the Daily Mail in print feels it has to resort to a full page attack on the Guardian to make its point is that its take on life is largely indistinguishable from its online relation. Both have an obsession with women's bodies that mixes salaciousness with prudishness, both have at best ambivalent views towards foreigners, and both have a voyeristic obsession with crimes and disasters. If you could print out gifs, the Daily Mail would be putting animated car accidents or bombing runs on its front page the same way Mail Online does with its home page.

Sure the Mail Online’s staff are web savvy in a way that the Dacre and the rest of the print newspaper’s management would consider borderline heresy, but their approach to journalism stems from the same place, the same culture, and yes, the same worldview.

The Daily Mail's insistence that Mail Online is nothing to do with it is rather like a negligent father denying paternity of a wayward teenager still living under the same roof. Unfortunately, the DNA tests don’t lie. Give it up Daily Mail, you and Mail Online are part of the same (un)happy family.