A GNM spokesperson said: “We can confirm that Nick Cohen has resigned from GNM on health grounds.
“We would like to thank him for his long service and contribution.”
Observer editor Paul Webster said: “Nick Cohen has been a brilliant columnist whose incisive, emphatic writing has been a big part of the Observer for more than 20 years.
“On behalf of Observer colleagues, I’d like to thank him for his service and wish him all the best as he moves on to new opportunities.”
His departure follows an investigation over a number of complaints about Cohen’s behaviour in the office made by former female colleagues.
Despite the complaints, one Observer insider said they were “mystified” and “sad” about the manner of Cohen’s departure.
His last weekly Observer column appeared in July 2022 and the internal investigation has now concluded.
Allegations, which Cohen has described as “vile and untrue” in a legal letter, were circulating on social media at the start of 2020. Cohen engaged Patron Law over “seriously defamatory posts” that appeared on an anonymous Twitter account.
Jolyon Maugham KC, the founder and executive director of the non-profit Good Law Project, contacted GNM in late 2021 with concerns shared with him relating to Cohen from a number of sources.
London-based law firm Baker McKenzie contacted Maugham and others on behalf of GNM as part of an investigation by the publisher.
Freelance journalist and BBC One Show presenter Lucy Siegle, who worked her way up at GNM from an admin role to write an Observer column on ethical living and launch the newspaper’s Ethical Awards, raised a complaint relating to Cohen with management in February 2018.
It related to a workplace encounter some 17 years earlier which she later wrote about on Twitter in October 2021.
She met with a senior GNM executive but described the meeting as “aggressive” and an “absolute car crash” in which she felt “gaslit” and like they “basically spent half the time trying to diminish what I was saying and then the other half of the time sort of putting their fingers in their ears and almost going ‘la la la’,” she told Press Gazette last year.
He wrote: “There are millions of people who reject right-wing authoritarian populism and the left’s insistence on ideological conformism. This newsletter is for them.
“Although it will cover global themes, its focus will be on the UK. My country is both a warning to others and a morbid case study of what happens when loud-mouthed charlatans run riot.
“It’s for people who reject tribalism, who bristle when those in political and cultural authority tell others to avoid contentious subjects for the sake of keeping in with their peers.”
It costs £6 per month and according to Substack has hundreds of paid subscribers. Cohen also writes regularly for The Spectator.
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