The restaurant critic Jay Rayner left the Observer because “there are antisemites on the [Guardian] staff” and the editor, Kath Viner, “likes to deny it,” he wrote on a private Facebook post seen by the JC.

In the post, Rayner wrote: “I'm not sorry to be leaving Guardian newspapers. For years now being Jewish, however non-observant, and working for the company has been uncomfortable, at times excruciating.

"Viner likes to deny it but there are antisemites on the daily's staff and she has not had the courage to face them down. For years now I have made a point of sending her a back channel email each time the Guardian has published another outrage. It will be a joy to know that I'm not a part of that anymore.”

Other reasons for moving from the Observer to the FT listed in his post included “the juvenile hellscape of salami-sliced identity grievance politics that [the online opinion section] too often is” and the sale of the world's oldest Sunday newspaper to Tortoise Media.

“Viner's pursuit of the Tortoise deal has been absurd and deranged,” Rayner wrote. “It represents a failure of duty of care to her staff, and crass mismanagement. To value the Observer brand at £1 is craven. And Harding's Tortoise deal doesn't stack up.”

Rayner also highlighted that he was enthusiastic about joining the “authoritative, smart and entertaining” FT, emphasising that “I am going towards something”.

Last month, the Guardian issued an apology after a furious backlash over its review of a documentary on the October 7 massacre that criticised how the Gazan invaders had been “demonised” as "testosterone-crazed Hamas killers" and "shameless civilian looters”.

In an apology published on its website, the Guardian said while it believed that the review did condemn the “attack’s perpetrators”, it ultimately failed to meet the paper’s editorial standards in its criticism of the documentary.

Formerly one of the Observer’s highest-profile writers, Rayner had worked at the paper for 28 years. He was well-known for his no-holds-barred reviews of restaurants that failed to meet his standards.

The move comes amid reported turmoil at the Guardian Media Group (GMC) over the planned sale of the Observer, the Guardian’s sister paper, to Tortoise Media.

Journalists at the Guardian and Observer have voted to strike for 48 hours on Wednesday 4 December and Thursday 5 December over the deal.

Tortoise was founded in 2018 by former BBC News director and Times editor James Harding, with former US ambassador to the United Kingdom Matthew Barzun. It specialises in “slow news”, podcasts and events.

On Monday, the board of the Scott Trust, the Guardian’s ultimate owner, will have a discussion over whether to carry on supporting GMG’s intention to sell the Observer, according to Sky.

Tortoise has said that it would invest £25 million in the Sunday title over a five-year period, and has pledged to retain the newspaper’s focus on arts and culture.

A Guardian spokesman said:

“We take allegations of this nature extremely seriously. The Guardian Media Group has a zero tolerance approach to antisemitism and all forms of prejudice and discrimination. We have probust processes in place. When any allegations are made, we investigate them and deal with them swiftly.
“We recognise the strength of feeling about the proposed sale of the Observer. Our priority is to support our staff and serve our readers, so that the Guardian and the Observer can continue to promote liberal journalism and thrive in a challenging media environment.”

Katherine Viner has been approached for comment.