Police are urgently appealing for a "significant" witness to contact them after a woman was dragged to the ground and sexually assaulted in the Stockwell.

Detectives have released CCTV of a man they wish to identify who is described as a 5ft 5 "dark skinned European" with dark hair, possibly in his 20s.

In the image he is on Clapham Road, wearing a blue coloured jacket over a white shirt, dark red coloured trousers and brown shoes.

The victim, aged in her 20s, was attacked outside Strudwick Court in Binfield Road on Sunday, April 2 at around 4am.

Nearby members of the public heard her screams for help which caused the suspect to run away towards Stockwell Underground Station.

Specialist officers are supporting the victim.

Officers from the Sexual Offences, Exploitation and Child Abuse Command are investigating and are appealing for witnesses and information.

Detectives want to speak to a woman who they believed responded to the victim's screams for help and directed another to the scene who helped the victim.

Detective Inspector Suzanne Jordan, from the investigating team, said: "Stranger attacks of this nature are fortunately rare, and with this investigation we are working hard to identify a suspect and prevent any further incidents occurring.

"I am appealing to anyone who thinks they recognise the man in the CCTV we have released to contact us. Their information could be crucial to our investigation.

"We believe a number of people would have been in the vicinity at the time of the offence. We are urgently seeking to speak to any person who may have information in relation to this incident, or the identity of the assailant.

"We are particularly keen to speak to a woman, who we believe helped disturb the attacker making him flee the scene before anything worse happened. Hopefully this person will know who they are, as they helped direct another man to assist the victim, and will contact us to assist our investigation."

Any witnesses, anyone who has any information, or anyone who recognises the man in the CCTV is urged to contact the investigation team on 020 8721 4106, or via 101, or by tweeting @MetCC.

To give information anonymously contact Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org.

There have been no arrests.