Police have rescued three women from a Lambeth property who have been held hostage for at least 30 years, one for her entire life.
A 30-year-old British woman, a 57-year-old Irishwoman and a 69-year-old Malaysian woman are believed to have walked to their freedom after media coverage on forced marriages gave them the courage to contact a support charity.
The 30-year-old is reported to have spent her entire life in captivity.
Investigating officers said they had "never seen anything of this magnitude before".
Two people - a 67-year-old man and a 67-year-old woman - have been arrested.
Det Insp Kevin Hyland said: "All three women were deeply effected and traumatised.
"Their lives were greatly controlled. For much of it, they would have been kept on the premises. The women were recovered some weeks ago but the arrests were made this morning."
Aneeta Prem, Freedom Charity founder, said the alleged victims - who are believed to have suffered physical and mental harm - were able to walk out of the property after extensive calls with the charity.
She told Sky News: "We started in-depth to talks to them when they could, it had to be pre-arranged. They gave us set times when they were able to speak to us.
"It was planned that they would be able to walk out of the property. The police were on standby.
"They were able to leave the property, but it was done in such a way... it was a very, very excellent way it happened.
Ms Prem said the two people arrested were considered the "heads of the family", and that the women were "absolutely terrified" of them.
She added: "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.
"We absolutely thrilled this has happened."
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Asked about what help the women will be given, the charity founder said: "They are going to be afforded all the help and support that can be.
"I'm so grateful they saw the news.
"Now they will try to re-build their lives."
The Met Police statement reads...
Officers from the Met’s Human Trafficking Unit arrested two people in their 60s at their home in south London this morning as part of an investigation into slavery and domestic servitude.
The two suspects, a 67-year-old man and a 67-year-old woman were taken to a south London police station where they remain in custody.
Police were contacted in October by Freedom Charity after they had received a call from a woman stating she had been held against her will in a house in London for more than 30 years.
Further enquiries by police revealed the location of the house and with the help of sensitive negotiations conducted by the charity the three women, a 69-year-old Malaysian woman, a 57-year-old Irish woman and a 30-year-old British woman were all rescued.
All three women, who were highly traumatised, were taken to a place of safety where they remain.
Detective Inspector Kevin Hyland, from the Met's Human Trafficking Unit, 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."
He continued: "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."
Earlier this year the Forced Marriage Unit (FMU) - a joint operation by the Home Office and the Foreign and Commonwealth Office - revealed it helped in 1,485 cases of possible forced marriage in 2012, involving 60 countries across Europe, Asia, the Middle East, Africa and North America.
The statistics for last year show that of the 744 cases where the age was known, more than 600 involved people under the age of 26.
Evidence is currently being reviewed by parliamentary group for a proposed Modern Slavery Bill, led by Labour MP Frank Field.
Field said the horrific details of this case “emphasise the crucial need for a new Modern Slavery Bill, along with immediate practical measures to tackle modern slavery, which we are now increasingly aware is taking place through many insidious forms across the country.
"We need police forces to be working much more closely with local NGOs, such as Freedom Charity, to help raise awareness and spot the signs of this evil, which is taking place right under our noses.
"It was incredibly brave for one of the victims to call for help – much more needs to be done to help victims come forward.”