A MOTHER has told a jury how she got embroiled in an argument at a party because her son was being repeatedly attacked by a gang - saying: "I'm a mum, that's my job."

Samantha Firth-Corner said she was scared when she was confronted by one of the teenagers in the garden of a house in Bedale, North Yorkshire, in April last year.

The 15-year-old lost significant parts of his two front teeth in the clash, and the prosecution say Mrs Firth-Corner smashed him in the face with an A4-sized rock.

The mother-of-three - on trial for assault - said the stone was about the size of a grapefruit and she forgot it was in her hand when she "pushed" the youngster.

It is said that there was bad-feeling among two families and friends over the smoking of illegal highs and Mrs Firth-Corner's daughter wanting to stay at the party.

But she told prosecutor Victoria Lamballe, at Teesside Crown Court: "There was not a problem that night. You are putting something there that was not there."

The 43-year-old gave emotional evidence yesterday, shaking and voice breaking as she told of the horror of seeing her son "pounced on" by up to five people.

"He was being punched and kicked while he was on the ground," said Mrs Firth-Corner. "He needed help. I needed to stop it or else how long was it going to go on.

"I think you would have to be in that situation," she said, fighting back tears. "I just wanted to stop them. I wanted to protect my son. I'm a mum, that's my job."

She said the lad who was injured by the rock came at her saying "He's not such a big boy now, you're boy, is he?" as he was being beaten up on the ground.

The prosecution case is that Mrs Firth-Corner and her son had gone to the house looking for trouble, and she attacked the teenager after he asked: "What's your problem."

Answering questions from her barrister, Christopher Smith, she said: "My only thoughts were to go an scare them off. It was frightening. It was horrible."

Talking of the victim, she added: "I feel terrible the fact that the altercation had caused that to him. I have got teenagers . . . I did not hit that child."

The defendant, of Oak Tree Road, Bedale, denies a charge of assault occasioning actual bodily harm, and the trial is expected to continue tomorrow (Thursday, February 12).