A teenage girl may have talked a knifeman out of killing her after he abducted her and cut off a piece of her hair.

The terrified 17-year-old student was forced into an allotment and repeatedly threatened with a knife.

Her attacker kept her there for 20 minutes before making his escape.

Detective Sergeant Chris Standard said: "I think that her attempts to engage him in conversation might have saved her life.

The victim's ordeal started as she walked home through Tenantry Down Road, Brighton, at about 10.30pm yesterday.

A man with a hat and a scarf over his face approached her and produced a knife, then grabbed her by the hair and forced her to the nearby allotments.

He made her throw her mobile phone away and sit on a pile of rubbish.

He then lay down behind her and cut off some of her hair with the knife.

Minutes after the man left, the victim ran to the road and flagged down a taxi. She called police from her home.

She was being comforted by family and friends today and has been offered trauma counselling.

Her attacker was 5ft 8in tall, well built, in his early 30s and possibly bald, balding, or with a shaved head.

He had a distinctive two or three-inch goatee beard.

He wore a black bomber jacket, dark tracksuit trousers and a scarf and dark hat covering his face. He may walk with a limp.

The weapon was two to four inches long, possibly a kitchen knife.

Police are trying to trace a dog walker seen in the area at the time and motorists who were driving past.

Mr Standard said: "Motorists may have seen this man in the area. If you recognise him or saw or heard anything suspicious last night I urge you to call Brighton CID urgently."

Detective Inspector Russ Bagley said: "The victim was terrified but she did extremely well.

"This man needs to be caught and we urgently need help from witnesses."

Anyone with information should call Brighton CID on 0845 6070999 or Crimestoppers in confidence on 0800 555111.