A close friend of one of two lesbian lovers accused of stabbing a teenage boy 23 times told a court she had an explosive temper.

Jon Fynche, who is 6ft 4in high and weighs 20 stone, told a jury at Lewes Crown Court how he had once had to restrain Gemma McGarvie when she flew off the handle.

He said: "An ex-girlfriend of hers appeared on the scene with another girl. She spotted her in Littlehampton town centre. She went ballistic."

Mr Fynche described how he struggled to hold McGarvie, 18, back.

He said: "I had her in a bear hug. I was struggling to keep hold of her. I had to use most of my strength. She's particularly strong when she's in a temper. If I hadn't held on to her she would most likely have run towards this girl and attacked her."

Mr Fynche told the court how McGarvie had once armed herself with a carving knife when she became concerned a group of people were going to raid her flat. He said: "She paced up and down the flat holding the knife for about an hour."

McGarvie, of South Terrace, Littlehampton, and Lorraine Large, 22, of Foxes Court, Barnham, both deny the charge of attempted murder of the 13-year-old and an alternative charge of wounding with intent to cause grievous bodily harm.

The court heard how McGarvie had lost her temper when the teenager was sick in her flat during a party on December 14 last year after drinking a bottle of strong cider.

Mr Fynche said McGarvie became very angry and started swearing at the boy, who cannot be named for legal reasons.

Soon afterwards she and Large said they were going to walk him home, the court heard.

Neighbours told the court how they had heard the sound of breaking glass, shouting and a noise which sounded like "a little girl crying".

A mobile phone call at 3am to the ambulance service led to the boy being found lying in a pool of blood on an area of green near the seafront, barely alive. He survived but will be scarred for life.

The trial continues.