British police have rescued three women held as slaves for 30 years in a London house after one of them reported their condition to a charitable institution. According to the UK authorities, a couple, both 67 years old, were arrested on Nov. 21 inside a house in South London.

The British police made the arrest as part of an investigation involving cases of domestic servitude and slavery. An institution contacted the authorities in October to report that a woman had called and claimed she was held against her will for three decades, along with two others.

The authorities said the call was triggered by Sky News documentary about forced marriages. Upon investigation, the call's location was traced to a south London home. With the aid of Freedom Charity, a 30-year-old British woman, a 57-year-old Irish woman and a 69-year-old Malaysian woman were rescued after three decades of slavery.

British police said the three women were "highly traumatized" and immediately taken to a safe place. In a statement, authorities said serious allegations will be investigated, including claims of slavery.

Detective Inspector Kevin Hyland praised Freedom Charity for helping free the victims of slavery. It was not clear which of the women told the police that they were held for 30 years. No other information was given for the other two victims.

Freedom Charity Spokesman Aneeta Prem said upon receiving the call, the organization planned to rescue the victims. She added planning their escape took secrecy and sensitivity. She noted the safety of the women was their top priority.

It was the organization that gained their trust and encouraged them to leave the house.

The names of the arrested couple were not released. The British police could only reveal that they were both British nationals. The two were granted bail and released.

According to Anthony Steen, UK special envoy for human trafficking, he was not surprised when the case came out in public since there are many other cases of slavery in the country. He said people who were forced to become slaves were in British brothels.