Prostitutes in the capital are selling full sex for as little as £15, new research showed today.
Trafficked women's charity the Poppy Project surveyed more than 900 brothels and found many offered high-risk "services" such as unprotected anal sex for just £10 extra.
The charity said its investigation exposed the "disturbing prevalence" of prostitution across the capital.
Researchers posed as potential "punters" and phoned 921 brothels which advertised in local newspapers, and discovered that 77 different ethnicities of women were being offered for sex.
Many came from well-known trafficking hotspots such as eastern Europe and south-east Asia.
A number of premises offered "very young girls" but did not explicitly admit to having underage girls available, the Poppy Project report said.
Co-author Helen Atkins said: "This research shows the disturbing prevalence of the sex industry in every corner of London - fuelled by the demand for prostitution services.
"Multi-media misrepresentations of commercial sex as a glamorous, easy and fun career choice for girls and women further contribute to the ubiquity of London's brothel industry.
"However, for most women involved in prostitution, the reality is a cycle of violence and coercion, perpetuated by poverty and inequality."
The average price for full sex was just under £62.
Researchers were told 95 per cent of the surveyed brothels were in a residential location with a "discreet appearance".
One brothel told researchers they offered first-time customers a 50 per cent off voucher for their next visit.
A researcher said in the report: "I do remember there was a chain of south east London places which promised 'the lowest prices in London' and a place in Islington stood out as sounding particularly unpleasant and dodgy."