Detectives hunting a man who sexually assaulted a teenager have stepped up their efforts by putting up signs near where the attack happened in a renewed bid to trace witnesses.

The 16-year-old girl was walking to meet her boyfriend at the Watermill pub, on Basildon's Craylands estate, on December 20, when the attack happened.

As she walked through an alleyway linking Humber Way with Wells Gardens, she was approached by a man asking for a light.

He then dragged her into an alleyway, before threatening her with a knife and subjecting her to a terrifying sex attack.

No-one has been arrested, leading officers to put up signs on the estate.

Acting Insp Mark Rayner said: "This attack was extremely serious and terrifying for the young victim.

"We would like to hear from anyone who may have seen anything, or who may have useful information, as the sooner we get this man off the streets, the better."

The attacker is described as black, with very dark skin and a wide nose.

He is of average build, around 6ft tall and aged between 16 and 24.

He wore a distinctive knee-length black woollen coat with toggle buttons, a black jumper, black boots and a cream beanie hat.

Anyone with information should call 01268 532212.