Southwark Police have released an e-fit of a man they wish to talk to in relation to a sexual assault in Bermondsey last month.
As she attempted to run he took hold of the back of her skirt and grabbed her buttocks.
The victim turned and challenged him and after a short confrontation he turned and ran off back down in the direction of Weston Street.
"This was a frightening ordeal for the victim which took place in a public street," says Detective Constable Kent Mossop from Southwark's priority crime unit.
"If you remember seeing anything suspicious in the area at the time of this incident or recognise the suspect from this e-fit please contact police."
Anyone with information should contact DC Mossop at Walworth police station on 020 7232 6195.