Eight men have been arrested and 11 women rescued during raids at suspected brothels.
Police raided 15 sites on Tuesday night where they found Romanian and Hungarian women, in their 20s, believed to be victims of sexual exploitation.
The searches, in Luton, were part of an investigation into human trafficking, exploitation and modern day slavery.
The men were arrested on suspicion of the management and control of brothels and money laundering.
They include six Romanians, one Hungarian and one Briton and are in custody at Luton police station.
‘Tip of iceberg’
The raids were part of Operation Thame and the latest intelligence-led operation involved 150 police officers and specialist staff.
Officers seized substantial amounts of cash and at one property three officers were attacked with pepper spray.
The rescued women spoke little or no English and were taken to a place of safety.
Insp Jim Goldsmith said some women are offered contracts to come to the UK to work in a proper job but “unfortunately that’s not the case” and the raids were the “tip of the iceberg”.
“We’ve seen quite a dramatic rise over the last eight to nine months in the off-street sex trade in Luton which has seen numerous brothels open and as such, has prompted the action we’ve taken.
“We try to keep these woman as safe as we can and that was the purpose of [these raids] to take the women out of that environment, give them the opportunity to exit that life and get them back to their families.”