The charity said police operations targeting begging by Romanian nationals around Marble Arch had also identified an increase in prostitution around nearby Park Lane.
The study, by Eaves for Woman, said a ificant proportion of prostitutes in the capital were from the eastern European country. It was also claimed many were suspected trafficking victims and were controlled by organised criminals. Chief Executive Denise Marshall said: "No matter where you stand on prostitution, the levels of violence and abuse escots women suffer, both entering and during prostitution, are too severe for us to ignore.
The charity said the prostitutes targeted hotel entrances in areas popular with tourists. Eaves has called for an immediate investigation into whether the Romanian prostitutes had been trafficked.
More on this story. The report, which covered the captal's 33 boroughs, said London's sex trade was "thriving".