A TEENAGER violated another schoolgirl with a spanner when she discovered the victim had slept with her boyfriend, a court heard.

The 17-year-old girl launched a "violent and sexual" attack when the victim, aged 14, confessed during a drunken house party in Bexleyheath.

Prosecutor Hannah Duncan told Inner London Crown Court: "They had a fight which other teenagers joined in with.

"The victim was dragged into the bedroom and held face down on the bed."

The 14-year-old, who cannot be named for legal reasons, was then abused with the wrench and made to lick it.

The victim was then attacked again by the 17-year-old, who also cannot be named.

The 17-year-old admitted what she had done after she was arrested on the day of the attack, March 17.

She pleaded guilty to two charges of assault occasioning actual bodily harm, an assault by penetration and false imprisonment.

The girl gave evidence against a boy at trial and said he was responsible for inserting the spanner but he was cleared by a jury on the charge of assault by penetration.

Judge Quentin Campbell told the girl an adult could have been jailed for up to 12 years for what she had done.

He said: "The offences can hardly be more serious.

"This was a violent and sexual group attack on a young victim.

"You appear to have gone substantially off the rails."

The 17-year-old, who lives in Woolwich, was sentenced to 30 months' detention in a young offenders' centre for the assault by penetration but was given no separate penalty on the other charges.