From the BBC:

The Newspaper Society is updating its guidelines on those adverts which should be accepted on classified pages.

It wants its members to be especially aware of the link between organised prostitution and human trafficking.

The society has already advised its members on how to spot adverts which might be promoting sexual services.

For example it tells them to be wary of ads for massage parlours, which might be a front for brothels.

The society, which represents most local and regional papers, is suggesting they simply refuse such ads.

It also suggests that payment be made by card or cheque so accounts can be traced, and that papers consult with police.

Human Trafficking is a $32 billion industry.