Judge Nicklin heard preliminary arguments from lawyers representing the two women on Monday.
In a written statement, Ms Riley told the court: “I believe I was targeted by the accused for criticizing the Labor Party’s handling of anti-Semitism.
“It was an attempt to silence me or stop people from listening to what I was saying by telling people that I was encouraging people to commit violence against Jeremy Corbyn.”
She continued, “The response to the defendant’s defamation against me was a concerted attack on me and my career.
“My career is in the public domain.
“A concerted campaign was launched to get me fired from my job because I was someone who advocated violence. “
Ms Riley told the court she had suffered a “wave of abuse” which prompted her to take steps to improve her “personal and domestic security” because she feared she would now be the target of retaliation.
“I was concerned that the accused’s tweet would encourage vigilance against me,” she said.
“I was very worried that I could be easily found because I am a public figure. “
Ms Riley claimed her “good advice” tweet was sarcastic and intended to show Mr Jones’ hypocrisy and the left’s “selective support” for acts of violence against politicians.
“Owen Jones’ most important position is that of champion of the left, cheerleader of Jeremy Corbyn, and I was highlighting the type of attacks he made,” she said. to the court.
Ms Riley claims she did not intervene and clarify what she meant in her tweet due to advice she received on how to deal with negative Twitter reactions from the Center for Countering Digital Hate.
Williams McCormick QC, on behalf of Ms Murray, said: “You could have just jumped in and said, ‘I can see a disagreement is going on, that’s what I meant’. “
“The advice is not to interfere,” Ms. Riley said.
“If I had to do that, I would only be promoting something that I don’t agree with.”
Ms Murray denies defaming Ms Riley, arguing for truth, honest opinion and responsible posting in her tweet.
The case before Judge Nicklin continues.