Oluwakemi Ajose, 19, and Hatice Can, then aged 13, subjected Rosie Boxall to a campaign of abuse for two years before she leapt to her death from the window of the older girl's flat in Blackheath, southeast London.

Miss Boxall, also 19, was punched, slapped, pulled by her hair, sprayed in the eyes with deodorant and branded a "whore" and a "slag" by her former friends.

In the minutes before her death she was filmed on a mobile phone as the "controlling and violent" younger Hatice Can, now 15, ordered Ajose to slap her around the head and pull her from a chair by the hair.

Rosie leapt 30ft to her death to escape her tormentors.

Minutes before she jumped from the third floor window, she was told by Can: 'Do you want to die? Jump out of the window.'

When Rosimeiri replied: 'Do you want me to jump?' the 13-year-old said simply: 'Yes'.

As she lay dying on the concrete the Can told her: "Serves you right, bitch."

Can was jealous because a boy had said he liked Rosi better than Can.

An Old Bailey jury convicted both girls of manslaughter after a three-week trial. They will be sentenced on December 15 and face lengthy spells behind bars.

Can had spent much of the trial talking to friends on her mobile phone and laughing as she tried on her barrister's wig and gown - apparently unaware of the seriousness of her position.

Roger Smart, prosecuting, had told them: "Rosie leapt to her death from the kitchen window of Kemi's flat to escape from a prolonged period of physical and verbal abuse. Immediately before Rosie fell, she was clearly in fear of being hurt physically. This fear caused her to leap out of the window, as a result of which she met her death."

Miss Boxall, whose adopted father, the Rev Simon Boxall, ran a community church in Thamesmead, southeast London, had left home the previous year. In March 2007 she dropped out of college and two months later ran away from home to live with Ajose.