However Snopes (urban legend debunkers) doubt it, and it seems to be contradicted by this reuters article (' spokesman for the Federal Labour Office said job centres would not advertise this type of post')
I think this legend fascinates lefty/feminist bloggers as a (supposed) example of the way capitalism sexploits women, and it satisfies social conservatives ('just look what happens when you liberalise sex laws'). It fascinates Americans ('these loony Europeans').
Most illogically it appeals to libertarian types ('socialism and welfare benefits force people into sex slavery'). However, this last point of view is obviously total gubbins, as the libertarian alternative is to offer no benefits at all, thus forcing women into the sex trade through poverty (as happened in the 19th century, and still happens in the third world).
The Telegraph should know better than this, and they quite rightly end up looking like fools.