Eleven women have been rescued from several brothels that were raided by police in Luton.
Officers also arrested eight people following an investigation into human trafficking, which saw 17 properties in the borough searched on Tuesday evening.
Bedfordshire Police worked with the National Crime Agency and support workers from Luton Borough Council and the human trafficking charity Azalea during the operation, which also saw a child rescued from one of the properties.
The women, who are from Hungary and Romania, have been offered support through the national referral mechanism for modern slavery victims.
Police Inspector Jim Goldsmith said: "Women in this industry are often lied to, coerced and abused, as well as being plied with drugs and subject to debt bondage in order to line the pockets of criminal gangs.
"We won't stand for this and yesterday's action was just the start of our efforts to dismantle the criminal networks behind these brothels and bring their ringleaders to justice."
Azalea chief executive Ruth Robb described the operation as a "massive success".
She said: "We are huge believers in partnership working to address this problem and end the commercial sexual exploitation of women.
"This was a perfect example of such work, with the police, ourselves and other partners providing a holistic service to potentially protect vulnerable victims."
If you have information about a suspected brothel, report it to police on 101 or via the Modern Slavery Helpline, anonymously, on 08000 121 700.