Seventeen people have been arrested on suspicion of being involved with an international human trafficking group, as almost 30 women were led to safety.
Those arrested are between 17 and 50 years of age and include 14 men and three women, the Metropolitan Police said.
All are in custody at a central London police station.
Scotland Yard raided properties in Redbridge, Havering, Barking and Dagenham, Newham, Brentwood and Tower Hamlets in the early hours of Thursday.
Those held were arrested suspicion of modern slavery, controlling prostitution, Class A drug offences and section five firearm offences, relating to a stungun.
An additional four warrants were executed simultaneously in Romania, with one man being attested in Constanta, in the south east of the country.
A total of 29 women, aged from 20 to 40, were led from the addresses and taken to a safe place.
A number of charities and organisations including the Church of England and Refuge supported the operation, which was in the latter stages of an…