Messages of support have been sent to a 15-year-old girl after she was subjected to a torrent of “vile abuse” on social media after winning a competition with a speech calling for a free Palestine.

Redbridge Police are investigating allegations of malicious communications after a video of Leanne Mohamad’s speech went viral on social media.

Leanne was accused of a “blood libel” against Israel, of exaggerating the number of Palestinian children killed, and even of being an Isis recruiter.

The organisers of the Speak Out Challenge said they would “not tolerate the trolling of young people” after Leanne, of Ilford, was harassed for calling for an end to discrimination against Palestinian people.

Bob Hamlyn, head at Wanstead High, where Leanne is a pupil, also denounced the use of social media to harass her.

The school had to suspend its social media accounts after receiving “inappropriate” comments and Mr Hamlyn added Leanne and her family were receiving pastoral support.

“Using social media to harass anyone, especially a young person, is always completely wrong,” he said.

At the event, run by the Speakers Trust and Jack Petchey Foundation, Leanne’s Birds Not Bombs speech condemned “aggression, oppression and injustice” against Palestinian people.

“If I make a mistake you blame it on me and not on my religion because terrorism has no religion,” she said.

Born in London to Palestinian parents, Leanne said: “I am a 15-year-old child and should not be subjected to the vile abuse that I have been receiving.

“It has not lowered my confidence as I will continue to speak out with my personal thoughts and beliefs as I believe everyone should.”

Leanne’s mother Hanadi Souleiman told the Recorder she was concerned about her daughter’s safety and was horrified at the cyber bullying.

“She was so proud that she had won and everything happened after that,” she said. “She has been abused and harassed as a child, as a 15-year-old, it’s really not fair. She is receiving a lot of hate.”

She added Leanne was “aware of the suffering of the Palestinians” having visited family who had taken refuge in Lebanon.

Leanne’s supporters claimed she had been “silenced” after she was not put through to the overall final, and the Speakers Trust removed the video of her speech from the internet.

But the Speakers Trust said the video was temporarily taken down for “safeguarding” reasons, and insisted the decision not to select her for the final was made prior to any complaints being made.

Rabbi David Hulbert, of Bet Tikvah Synagogue, Newbury Park, recognised Leanne as a very good speaker “driven by her desire to influence and full of passion and energy” but believes the speech did not have a place in the competition.

“She should have been advised by the school to dominate her emotions and passions and bring more nuances.”

Rabbi Alex Chapper, of Ilford Federation Synagogue, Ilford, said she had been “let down by adults” and had been “ill-advised” to speak on such a sensitive topic.

But East London Three Faiths Forum’s Khola Hasan said people should not be victimised for saying what they think.