Three women enslaved for 30 years have been rescued from a house in London including one who has spent her entire life in domestic servitude, police say.

Officers, who arrested a man and a woman, both 67, at their south London home, described it as the worst case of modern slavery to have emerged in the British capital.

The suspects, understood not to be British nationals, were later released on bail.

Police said they did not believe the women - a 69-year-old Malaysian, a 57-year-old from Ireland and the 30-year-old Briton - were related and there was no evidence of sexual abuse.

It was not clear where the youngest of the three was born.

The women appeared to have had limited freedom over the years but it was not until one victim summoned the courage to call a charity after watching a documentary on forced marriage that their plight came to light.

They were rescued several weeks ago but the case kept secret until Thursday's arrests.

"All three women, who were highly traumatised, were taken to a place of safety where they remain," Kevin Hyland, detective inspector, said.

"The Human Trafficking Unit of the Metropolitan Police deals with many cases of servitude and forced labour. We have seen some cases where people have been held for up to 10 years, but we have never seen anything of this magnitude before."

Few other details were immediately available, but the fate of the women evoked memories of lengthy abductions in the US and Austria.

Hyland said the trail to the women began last month when the Freedom Charity reported a call from a woman who said she had been held against her will in the house after the organisation featured in the documentary.

Further inquiries led to a nondescript house in south London and, with the help of negotiations conducted by the charity, the rescue of the three women.

Source: Al Jazeera and agencies