Police have hailed an operation to smash an internet prostitution ring as a "major success".
Fifteen people were arrested as more than 100 officers swooped on a number of premises across central London.
Those arrested are suspected of being part of a criminal network involved in people trafficking and controlling prostitution, police said.
It is thought the network had been using an internet escort agency site as a front for organised prostitution.
Officers said the network trafficked the majority of women from Thailand and then coerced them to work as prostitutes.
A total of 110 officers were involved in Operation Gib, led by the Metropolitan Police with support provided by Surrey Constabulary and the Norfolk Constabulary.
Police said they had removed 30 women from a number of premises who they believe had been coerced into working as prostitutes for the network.
Speaking following the arrests, Chief Superintendent Ian Dyson from the Met, said that internet prostitution was a growing problem: "We arrested 15 people who we believe are involved in a criminal network and who were controlling women for the purpose of prostitution.
"Those 15 have been arrested for offences of trafficking, controlling prostitution and money laundering, and they have been taken to a police station and will be interviewed. We've also recovered 30 women who we believe have been exploited by this criminal network for the purposes of prostitution.
"For us it's been a very successful culmination of a three or four month operation which will continue into next week."
