A man who sexually assaulted three women and performed a sex act in front of a fourth as they travelled on buses is being hunted by police in London.

Scotland Yard said four women - aged between 19 and 31 - had been the victim of attacks in September and November last year.

In the first three cases, the suspect sexually assaulted the victims. The fourth offence was one of outraging public decency, it added.

Detectives have released CCTV footage recovered from a bus showing images of a man and are appealing to the public to help identify him.

The suspect is described as black, aged between 25 and 35, around 6ft tall and with short black hair.

“These incidents have left the victims feeling very frightened and violated," said Detective Constable Clare Beauchamp. "I am appealing to the public to help identify and locate this man as quickly as possible.

"Although none of the victims have suffered physical injury, the effects of becoming a victim of sexual assault can be lasting and traumatic."

Police said the first sexual assault took place at 1.30pm Tuesday 11 September on a route 253 bus near Camden Road Station. A second sexual assault was carried out at 7.45pm on Wednesday 21 November on a route 149 bus near St Leonard’s Hospital in Islington.

The third took place shortly before midnight on Saturday 23 November on a route 91 bus near Kings Cross Station.