Officers were called to reports of a “sexual assault” in southeast London on Sunday morning, the Met Police has said.
The Met said officers were called at 5.23am following an incident near St George’s Way.
A 25-year-old woman was taken to hospital for assessment and is being supported by specialist officers.
A 31-year-old man has since been arrested on suspicion of rape and robbery, and remains in custody.
Anyone with information should call the police on 101 with the reference 1448/25SEP.
Information can also be provided to Crimestoppers, anonymously, on 0800 555 111.