One of the finalists in the X Factor television talent show has been forced to quit after she was caught on video assaulting another girl.

Emily Nakanda, 15, is seen grabbing the girl's hair and throwing her to the ground before punching and kicking her.

The contestant withdrew from the show today after producers were alerted to the video by a national newspaper. A spokeswoman said that Emily had been dropped after stills of the footage was published in The Sun. Other footage of her threatening to gouge a boy's eyes out with a knife also emerged this week.

"In response to the stories in the papers this week regarding Emily Nakanda, we have conducted our own investigations into the matter and we can confirm that she has chosen to withdraw herself from the competition with immediate effect,” the spokeswoman said.

The latest footage, which was recorded on a mobile phone, shows Emily putting another girl, known only as Anna, in a headlock and pulling her hair. Emily tells Anna that she is going to rip out her hair and complains: "“If it rips out I’m gonna get blood on my clothes."

Sharon Osbourne, a judge on the show who acted as a mentor for Emily, said: “I am deeply saddened by this whole situation.”

Louis Friberg, Emily's mother, said that the family was “very disappointed” with her daughter’s behaviour. “As a family we are heartbroken and are very disappointed with Emily’s behaviour. We feel that there is no choice but to withdraw Emily from the competition. Emily and all the family sincerely apologise to both Anna, her school and all the fans that have supported Emily. Emily regrets her actions but there is no way, as a family, we can excuse her behaviour.

“Emily is very sorry to have let the show, Sharon and the viewers down.”

The girl has previously claimed to be in a gang and called herself “Lady Shiverz”.

She was criticised by the judges on Saturday for her performance of the Britney Spears song Not A Girl, Not Yet A Woman. Simon Cowell, another judge in the contest, said that the poor performance put her position on the show in doubt.

Emily was due to be singing the Bjork hit It’s Oh So Quiet on Saturday’s show. Ladbrokes, which had placed her as second favourite to win the contest, said it would refund all bets on the teenager.

An X Factor spokeswoman said the competition would air as usual on Saturday.

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