An MP's appeal against her harassment conviction and sentence has heard how she was driven by "obsession" and "jealousy".
Claudia Webbe, former Labour MP for Leicester East, was given a suspended sentence in November for harassing Michelle Merritt.
Southwark Crown Court heard the reason for the harassment was Ms Merritt's friendship with Webbe's boyfriend Lester Thomas.
The appeal will continue next week.
The court heard the campaign of harassment began with silent phone calls in September 2018, then "escalated" on 31 March, Mother's Day, the following year when Webbe questioned why Ms Merritt was in touch with her boyfriend.
"This appeared to be her obsession," prosecutor Susannah Stevens said. "The fact Ms Merritt should not be seeing or having contact with Lester Thomas."
Ms Merritt said Webbe, 57, started calling her names and told Ms Merritt she would send intimate pictures of her to Ms Merritt's daughters.
Ms Merritt said she felt "horrible", adding: "I certainly didn't want to be harmed in any way. I was very frightened and shaking."
The witness said she called police and said: "I have been threatened by a public figure with acid."
The court heard she received 17 further phone calls lasting 14 seconds or less from Webbe after the MP was warned by police to stop contacting her.
Ms Stevens added: "It was this jealousy that caused her to threaten Ms Merritt and to say deeply distressing things to her."
Webbe entered the Commons in December 2019, winning the seat formerly held by Keith Vaz.
Labour, which confirmed Webbe had been expelled from the party, has said it will push for a recall petition to force a by-election if she does not quit the Commons.
The appeal will continue on Wednesday.