London's Metropolitan Police spoke about the rescues after two people - a man and a woman, both 67 - were arrested early Thursday as part of an investigation into domestic servitude.
Scotland Yard's slavery investigation was launched after one of the captive women contacted a charity to say she was being held against her will and the charity went to the police, the force said. Those freed on Oct. 25 are a 69-year-old Malaysian woman, a 57-year-old Irish woman and a 30-year-old British woman, police said.
Kevin Hyland, head of the Metropolitan Police's human trafficking unit, said all three women were "deeply traumatized."
Police said they do not believe any of the victims are related and there was no evidence of sexual abuse. Hyland said he didn't know of any of the relationships between the women or their suspects, including whether the suspects were a couple.
The revelations raised numerous questions - all still unanswered - about how the women's ordeal began and why it endured for so long. What brought them to London? What freedoms - if any - did they have? What restrictions and conditions were they were subject to? Did neighbors ever see them, did they ever try to escape?
The women - whose names have not been released - are now safe at an undisclosed location in Britain and have been working with severe trauma experts since their rescue, Hyland said.
It is not known how the women ended up in the house - especially the 30-year-old, who would have had to either been born in the home in the Borough of Lambeth or enter it as an infant, given the police timeline. She appears to have been held in domestic servitude for her entire life, Scotland Yard said.
Hyland said police were contacted in October by Freedom Charity, who told them it had received a call from a woman who said she had been held against her will in London for more than 30 years.
The Irish woman called Freedom Charity from what appears to be an "ordinary house in an ordinary street," said Aneeta Prem, founder of the charity that promotes awareness of child abuse, forced marriages and honor killings.
Police said the catalyst for the woman's call was a television documentary on forced marriages. What followed were secret, "in-depth" conversations with the women, Prem told Sky News.
"It had to be pre-arranged when they were able to make calls to us and it had to be done very secretly, because they felt they were in massive danger," she said.
Police scrambled to track down the house in the borough of Lambeth, a large, mixed residential neighborhood south of the River Thames. Prem said the women were able to walk out of the property - with police on standby - after those repeated, tentative calls.
Hyland said there was a delay in arresting the two suspects - neither of whom are British - as police worked to establish the facts of the case and to ensure that the women who had escaped were not further traumatized.
"When we had established the facts, we conducted the arrests," Hyland told reporters.
London police were keeping the exact location of the house secret and would not disclose the nationality of the suspects, who were being held in a south London police station.
Hyland said while the women had some "controlled freedom," police were still working to establish how much and what sort of conditions they lived under for the past 30 years.
"For much of it, they would have been kept on the premises," Hyland said.
He said his unit, which deals with many cases of servitude and forced labor, had seen previous cases of people held for up to ten years.
"But we've never seen anything of this magnitude before," he said.