ITV News Central have had exclusive access as Nottinghamshire Police targeted suspected brothels in a crackdown on modern slavery.
Officers carried out a series of raids as part of an ongoing investigation into human trafficking and modern slavery.
Officers targeted a suspected brothel in the Hyson Green area of the city and another house where there was evidence of sex work activity.
Women in the houses were living with partners and working as prostitutes.
Workers in the sex trade are often lured to the UK under false pretences, exploited and tend to earn a fraction of the price for what they do.
Detectives say that in some cases families of workers are intimidated to keep them working and in extreme cases violence and drugs are used.
In Nottinghamshire, it's estimated around 800 people are currently being exploited as modern slaves.
Working in industries as diverse as agriculture, domestic service, even car washes.
The force's modern slavery unit, suspects they're only scratching the surface of the problem.
- If you’re concerned for someone or are experiencing slavery you can call 08000 121 700 for confidential advice, or visit www.modernslaveryhelpline.org