Women Were 'Kept As Slaves For Over 30 Years'
The inquiry was launched after one of three alleged victims told a charity she had been held against her will for more than 30 years.
Scotland Yard said the Freedom Charity, which advises and supports victims of forced marriages or honour-based violence, got in touch after they received a call following a TV documentary.
Further inquiries by police revealed the location of the house and with the help of sensitive negotiations conducted by the charity, the three women were rescued.
One was a 69-year-old Malaysian woman, the other a 57-year-old Irish woman and the third a 30-year-old Briton.
All three, described by police as "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.
"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."
Officers said the two suspects, a man and a woman, both aged 67, have been taken to a south London police station for questioning.
The call which triggered the police investigation is believed to have been prompted by a television documentary on fake marriages in the UK shown in the summer.
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.
These involved 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.