Nineteen women have been rescued during several raids across England by police targeting sex traffickers.
A man and his partner were arrested at a London hotel
More than 50 officers carried out a series of dawn raids at seven addresses in London, the West Midlands and Hertfordshire, arresting 12 people.
Thirteen women were found at a suspected brothel in west London and six in another in Birmingham.
It is thought to be the largest number of sex trafficking victims rescued in a single police operation.
A man was arrested with his partner at a hotel in Golders Green in north London.
The suspected traffickers are thought to be from Vietnam and the women appear to be from Malaysia.
The raids were carried out under Operation Pentameter, a national campaign launched in February to help women brought into the country and forced into prostitution against their will.
Wednesday's operation was led by a Metropolitan Police unit and followed a five-month intelligence operation.
Ch Supt Ian Dyson, the head of the clubs and vice specialist unit, said: "To people who organise women in this fashion and traffic women into the country - we will find you and we will arrest you for it.
Before Wednesday's raids, 44 women and two girls had been rescued since February
The 46 alleged victims were mainly aged between 18 and 22, but one was 15 and one 17
The victims originate largely from eastern Europe and the Balkans as well as Thailand, China and Brazil
Pentameter involves all 55 police forces in the UK, Republic of Ireland and Channel Islands
Nearly 400 raids have taken place nationwide, 154 arrests have been made and £170,000 has been seized
So far suspects have been charged with offences including kidnapping, false imprisonment, controlling prostitution and rape
"To men who use brothels, my message is 'stop it'. You are fuelling this trade.
"To anyone who knows of women in this position, please come forward. We want to help women who are victims of this crime."
The women will be given access to specially-trained police officers, health professionals and social services.
The Salvation Army has offered to provide accommodation for the victims.
Some will eventually return home and Mr Dyson said police were working with a charity in Malaysia to facilitate that.
Of the 11 men and one woman arrested, 10 are being held in London, one in the West Midlands and one in Hertfordshire.
They will all be taken to a central London police station for questioning.
In addition to the 12 arrests, two men were detained by the Immigration Service.