Television presenter Rachel Riley has told a High Court judge she was subjected to a “concerted attack” two years ago after an aide to then Labour leader Jeremy Corbyn described her as “dangerous” and “stupid” in a tweet.

Ms Riley, 35, who appears in Channel 4 show Countdown, told Mr Justice Nicklin that she received an “onslaught of abuse” following Laura Murray’s March 2019 tweet.

She said a “campaign” had been initiated to “get me fired from my job, as being someone who had advocated violence”.

Ms Riley, who has sued Ms Murray for libel and wants damages, said the tweet caused “serious harm” to her reputation.

Ms Murray, who no longer works as an aide to Mr Corbyn, has mounted a defence.

She says what she tweeted was true, and reflected her honestly-held opinions.

Mr Justice Nicklin on Monday began overseeing a trial at the High Court in London.

Ms Murray had posted the tweet on March 3 2019, after an egg was thrown at Mr Corbyn, then the Labour leader, by a Brexit supporter when he was visiting Finsbury Park Mosque in north London.

She had been responding to a tweet posted by Ms Riley, Mr Justice Nicklin heard.

Ms Riley had initially posted a screen-shot of a January 2019 tweet by Guardian columnist Owen Jones, about an attack on former British National Party leader Nick Griffin, in which Mr Jones had said: “I think sound life advice is, if you don’t want eggs thrown at you, don’t be a Nazi.”

She had added, “Good advice”, with emojis of a red rose and an egg.

Later, Ms Murray had tweeted: “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.”

Mr Justice Nicklin had ruled at an earlier hearing that Ms Murray’s tweet was defamatory.

The judge had concluded that the tweet meant that: Ms Riley had “publicly stated” that Mr Corbyn had been attacked when visiting a mosque; that he “deserved to be violently attacked”; by doing so, she had shown herself to be a “dangerous and stupid person” who “risked inciting unlawful violence”; and, that people should not “engage with her”.

He has now been asked to consider whether serious harm was caused to Ms Riley’s reputation, and, whether Ms Murray had a “truth” defence, an “honest opinion” defence, or a “public interest” defence to Ms Riley’s libel claim.

Ms Riley said she was being “sarcastic” in her tweet and had not called Mr Corbyn a Nazi.

“The response to the defendant’s libel of me was a concerted attack on me and my career,” Ms Riley told the judge, in a written witness statement.

“My career is in the public domain.

“A concerted campaign was initiated to get me fired from my job, as being someone who had advocated violence.

She told the judge that she had received “a great deal of abuse” and said “most of it” was caused by Ms Murray’s tweet.

Ms Riley added: “Unsurprisingly, people thought very badly of me because they took what the defendant had said about me at face value.”

She said she had been afraid that the “false allegation” that she had “encouraged a violent attack” made her a target for reprisals.

Ms Riley told the judge of an “onslaught of abuse” and said she had taken steps to improve “personal and home security”.

“I feared that the defendant’s tweet would encourage vigilantism against me,” she said.

“I was very concerned that I could be easily tracked down because I am a public figure.”

She added: “The volume of abusive and threatening messages was all-consuming.”

Ms Riley, who studied mathematics at Oxford University, told the judge that she was “largely known” as a Countdown presenter and the show’s “numbers expert”.

She said she was Jewish and had a “hatred of anti-Semitism”.

“I have spoken out against anti-Semitism and continue to do so,” she said.

“The growth of anti-Semitism on the left of British politics led me to criticise the Labour Party under Jeremy Corbyn and certain of its supporters and sympathisers.

“My view is that the Corbyn-led Labour Party was fostering anti-Semitism.”

A barrister representing Ms Murray disagreed with the case put forward by Ms Riley.

William McCormick QC told the judge, in a written case outline, that Ms Murray’s tweet was “true”.

“The claimant (Ms Riley) chose to tweet to her 625,000-plus followers about a violent attack in a manner which was both stupid and dangerous,” he said.

“It was obvious that her tweet would provoke hostile reactions of the kind that did in fact emerge.

“What the defendant (Ms Murray) tweeted was true, reflected her honestly-held opinions and was a responsible exercise of her own rights of expression on a matter of real public importance.”

He said Ms Riley had “wrongly regarded” the libel claim as being part of a long-running dispute over anti-Semitism in the Labour Party.

Mr McCormick said the case was not about anti-Semitism but about the “need for restraint in public discourse”.