Rachel Riley has won the first round in her libel case against a former staffer who worked in Jeremy Corbyn's office.
The High Court ruled that Laura Murray's tweet about the Countdown presenter, sent in March 2019 when she was stakeholder manager in Labour leader's office, was defamatory under common law.
The action centres on a tweet Ms Murray sent in response to a tweet Ms Riley sent after Mr Corbyn was egged by a Brexiteer when he visited Finsbury Park Mosque.
Ms Riley, who is pursuing Ms Murray for damages, had tweeted "good advice" and a thumbs up when she shared an earlier tweet by left-wing journalist Owen Jones, who wrote in January 2019: "I think sound life advice is, if you don’t want eggs thrown at you, don’t be a Nazi."
In response, Ms Murray wrote: "Today Jeremy Corbyn went to his local mosque for Visit My Mosque Day, and was attacked by a Brexiteer.
"Rachel Riley tweets that Corbyn deserves to be violently attacked because he is a Nazi. This woman is as dangerous as she is stupid. Nobody should engage with her. Ever."
Ms Riley launched legal action.
In a judgment published on Friday, Mr Justice Nicklin said: "An imputation that a person had publicly supported a violent attack on someone is plainly defamatory at common law.
"It is conduct which would substantially affect, in an adverse manner, the attitude of other people towards the claimant or have a tendency so to do."
But Mr Justice Nicklin rejected Ms Murray's lawyer's claim that she was expressing an opinion when she asserted Ms Riley had said Mr Corbyn "deserved to be violently attacked".
He said this was "a simple factual statement and would be understood as such".