Analysis of more than 60,000 sexual adverts showed more than 60% of them demonstrated signs of trafficking and exploitation.
ITV News spoke to a woman who detailed her experience.
It comes as the anti-slavery commissioner says so called sex-for-sale websites can enable the exploitation of often vulnerable people to make money for organised crime gangs.
And she is calling for much tougher regulation of such websites.
If you have been affected by any of the issues raised in this report there is help and support available at itv.com/helplines
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