A general question really, as the info I have is hearsay only. Here goes though:
My cleaner told me today that she found out someone (who she doesn't know, only talked to her on the train) was promised a live in nanny job in London, so she came here from her home country. It's in Europe, and no visa restrictions.
Anyway, it now seems this girl is being paid £250 per month, has to look after 2 children under 5, 7 days a week, 24 hours. The mother doesn't work, but the girl has to do everything for the children, as well as cooking, cleaning for the family, etc. Oh, and it gets better: apparently she needs to share not only a room with the children, but a bed with the 4-year old. 
She is not allowed time off without the children, ever, even if she is ill. Apparently the mother got really annoyed when she asked to go for a walk once, grudgingly agreed, and after 30 minutes called her again to say one of the children needs a bath so she had to come home immediately.
This might, of course, not be true, but my cleaner, whom we have known for years and is an amazing woman and normally a good judge of character, was really upset about it. She said that she didn't know what to do, but that she would try to help this girl. All I could think of is to search au pair agencies, and Gumtree, and then apply from there? Her English isn't good enough to work as a nanny yet, and she doesn't have the experience either (in this job less than 6 months). I thought as she needs accommodation, and would be willing to work for little money, au pairing might be a good start? Any ideas? Thanks.