Two people have been arrested on suspicion of keeping three women as slaves in a house in Lambeth, south London, including one woman who claimed she was held captive for more than 30 years.
A man and a woman, both 67, were arrested by officers from the Metropolitan Police Human Trafficking Unit as part of an investigation into slavery and domestic servitude.
The suspects were being held in custody.
Police were contacted by Freedom Charity when its staff received a call from a woman who said she had been held against her will for more than 30 years.
Police tracked down the property - in an undisclosed part of the capital - and negotiated for the release of three women, a 69-year-old Malaysian, a 57-year-old from Ireland and a 30-year-old British woman.
All three were highly traumatised, said police, and were taken to a place of safety.
Det Insp Kevin Hyland said: "We applaud the actions of Freedom Charity and are working in partnership to support these victims who appear to have been held for over 30 years. We have launched an extensive investigation to establish the facts surrounding these very serious allegations.
"A television documentary on forced marriages relating to the work of Freedom Charity was the catalyst that prompted one of the victims to call for help and led to their rescue."
Aneeta Prem, the founder of Freedom Charity, told Sky News: "They felt they were in massive danger.
"I don't believe the neighbours knew anything about it at all. It was just an ordinary house in an ordinary street.
"They were very restricted on everything they could do.
"Now they will try to rebuild their lives."
Lambeth Slave Women's Suspected Captors were 'Nice Normal Couple'