He Labour The party has demanded the resignation of the MP found guilty of harassment.
Leicester East MP Webbey also said she would send nude photos of 59-year-old Michelle Merritt to her family.
Following the guilty verdict on Wednesday, a Labor spokesman said: “The Labor Party strongly condemns Claudia Webb’s actions and must now resign.”
Westminster Magistrates’ Court heard that Webb made the threats in a string of phone calls between 1 September 2018 and 26 April last year.
In one, Webb called Ms Merritt “a lava”, threatened her with acid and said she would send nude photos and videos to her daughters.
In another call recorded by the complainant, Webb was heard asking the victim to “get out of my relationship” about 11 times.
Webb, of Islington, north London, denied the harassment, claiming she had only made a “courtesy call” to warn Ms Merritt not to violate coronavirus rules by meeting with Lester Thomas.
Defending Paul Hines QC, he read a string of character references from figures including former Labor leader Jeremy Corbyn, ex-shadow chancellor. John McDonnell and former shadow home secretary Diane Abbott.
But Chief Magistrate Paul Goldspring found him guilty on Wednesday after a two-day trial.
“I do not think that the defendant is convincing, compelling and truthful in all aspects of his evidence,” he said.
“Some of the things she said, I believe, were made in the moment.”
He continued: “In short, I find Ms. Webe vague, inconsistent and sometimes illogical, and ultimately I find her untrue.”
Mr Goldspring adjourned the sentence until 4 November and released Webb on unconditional bail, but warned he could face prison.
“Throwing acid on someone and threatening to send intimate pictures to family members crosses the limit of custody,” he said.
Her lawyers said she would appeal the conviction and Webb said in a statement: “I am deeply shocked by today’s decision.
“I am innocent and will appeal against this decision.
“As I said in court and repeat now, I have never threatened violence nor have I ever harassed anyone.”
Webe, who entered the Commons in December 2019 after formerly winning the seat of Labor veteran Keith Vaz, was living with Mr Thomas at the time of the allegations.
The couple reached the court holding hands and they sat in the public gallery during the entire hearing.
Ms Merritt said she had known Mr Thomas for more than 15 years and that they were “good friends”, having already been dating.
Prosecutors said Webb made a series of silent phone calls from a withheld number before “increasing harassment” on Mother’s Day on March 31, 2019.
Giving evidence from behind a screen, Ms Merritt previously stated that Webb described her as “Lester’s girlfriend” in an “angry” call that culminated in ‘You’re a slag and you’re going to be acid’.
“She confirmed that she knows where I live and will send pictures and videos to my daughters,” she said.
Mr Goldspring said he was satisfied that Webb had “threatened to throw acid on Ms Merritt”, adding: “I think she was jealous of the relationship between Lester and Michelle, whatever the nature of that relationship.” Of course, she thought it was something she wasn’t happy with.”
Ms Merritt complained to the police, who warned Webb not to contact her, but the calls continued.
In a recorded conversation on 25 April last year, the MP can be heard saying: “I’ve seen all your nude photos, I’ve seen all your relationship with Lester, get out of my relationship, or I I’ll tell your whole family and show them all your pictures.”
Webb claimed she was having an altercation with Mr Thomas at the time and was referring to a picture of him “naked from the waist up” taken while on vacation in St Lucia.
She said she was asking Ms Merritt to get the relation in the context of the “unfair bubble” during the lockdown.
But Mr Goldspring described his explanation as “clearly unreliable and unreliable”.
Webb claimed she was the victim of “domestic abuse and coercive control” and said she was being “ged and gaslighted” during the row, resulting in the police being called after a neighbor reported her screaming. .
During the call, Mr Thomas can be heard asking his partner: “Are you crazy?”
Prosecutor Susanna Stevens suggested to the MP that the remarks were made “because you went crazy”.
Webb said: “I’m not crazy, I’m a Member of Parliament.”
In character references, Ms Abbott said that Webb was “very committed to working to support women”, describing her “warmly sympathetic manner”.
“I consider her to be a very honest woman,” she said.
Mr Corbyn said he is “very committed to ensuring the administration of justice” and is ready to “tell the uncomfortable truth when it matters”.
“I have no hesitation in recommending him as a man of good character who makes a positive contribution to our world.”