In a humiliating mistake for the network, CNN has had to correct a news story it ran hard on Friday, claiming that WikiLeaks offered the Trump campaign access to damaging emails before they were published on their site.

CNN based the story on an email, dated September 4 — before WikiLeaks published a trove of DNC emails — that gave Trump’s campaign access to the stolen Democratic National Convention emails. The network relied on the exclusive revelations for a number of segments, which were followed by other networks, until The Washington Post got its hands on the same email with the correct date — September 14, after the emails had been published by WikiLeaks.

CNN later published a correction, and has said its processes were followed but the sources for the story had made a mistake, and not intended to deceive reporters.

President Donald Trump, who has regularly claimed that CNN, among others, is “fake news”, mocked CNN at a rally, pretending to thank the network for apologising (which it has not). His son Donald Trump Jr used Twitter to characterise the story as fake news.

The high-profile cock-up is just the latest in a series of mistakes that outlets disliked by Trump have made. In July, three CNN journalists resigned over a story published connected Trump officials with a Russian investment fund without following its usual editorial processes.

Last week, an ABC journalist was suspended after a false report about former national security adviser Michael Flynn because he had not followed the usual editorial policies for sources. Bloomberg News and The Wall Street Journal both corrected reports that special counsel Robert Mueller had subpoenaed Trump’s records from Deutsche Bank.