A TEENAGER subjected to a terrifying sex assault was saved when her screams for help were heard by a late-night reveller.

The 18-year-old, who had been visiting a friend, was yards from her home in Stockton in the early hours of Saturday when she was attacked from behind.

A man in his early 20s, who spoke with poor English, had moments earlier asked her for sex. When she refused and walked on, he grabbed her by the hair and dragged her to the floor.

The girl was pinned to the ground as her attacker, of Asian appearance, covered her mouth and tried to rape her.

Detective Constable Jeremy Collins described the attack as nasty and unprovoked, and, although the victim received no physical injuries, she was left badly shaken.

He told how the girl, who had spent the evening at a friend's house, was dragged into Egglestone Terrace at about 2am.

She was saved when her screams were heard by a man returning from a night out in the town centre.

The 20-year-old chased off the attacker, who ran towards County Cars and then disappeared down an alley.

Det Con Collins said: "It was fortunate he heard her screaming and his intervention stopped the attack.

"Coincidentally, the victim and passer-by live close to each other and were both heading towards their homes when their paths crossed.

"It was extremely brave of him to chase the attacker and his actions saved the girl from a more serious assault.

"She was not physically injured, but she was clearly disturbed by what happened and what could have happened."

Det Con Collins said the Good Samaritan pursued the attacker along Leybourne Terrace, but lost sight of him when he ran down a dark alley close to a taxi rank.

The attacker, who had black, gelled hair, wore a light brown or dark grey leather jacket, light blue jeans and black shoes.

Det Con Collins said: "This was a nasty assault and he needs to be caught."

He urged any witnesses to contact him on (01642) 302226.