In my experience, yes. While it is certainly not ethnical, I have seen employers hire undocumented migrants because they can pay them less, and many undocumented migrants are willing to do jobs that nobody else wants to do. Undocument migrants will, because of the fear of being reported or deported, complete work for below minimum wage, without complaint. This is attractive to employers as they do not need to pay as much to have unattractive jobs completed. Unethical employers, or employers who are struggling with money, often hire undocumented migrants to keep costs low. Many employers may also use the threat of reporting these migrants to refuse raises, fair pay, or fair job duties. This essentially silences undocumented migrants and forces them to accept unfair treatment and pay.

Many employers, both small and large, see undocumented migrants as being a source of cheap labour. The protection afforded such workers is non-existent and this includes meeting minimal wage legislation in their adopted countries.

Cheap migrant labour is a problem in all developed nations including the US and throughout Europe and it is essentially employer driven. Cases have been reported where employers have provided workers with forged documentation which they then go on to accept as valid evidence of the entitlement to work in an effort to avoid prosecution for illegally employing workers. The acceptance of documentation as valid, but which turns out to be forged, is the most commonly used reason employers use to escape prosecution.

The onus then falls on the migrant worker, who is already in a position of vulnerability and finds it increasingly difficult to escape from the cycle of enforced labour. They have no entitlement to bring cases against their employer for monies owed in respect of overtime or holiday pay or sickness benefits.

One country which has improved the situation for undocumented migrant workers, is France. In 2011, with the support of unions who also have strong social commitments, undocumented migrant workers who were eventually returned to their country of origin, saw a law passed in December of that year which imposed strong penalties on employers and burdens which ensured workers were paid compensation, taxes and back wages. The result has been a reduction in the number of people specifically being brought into the country to work before transporting them home when they were no longer required.

Of course - you are not going to get premium rates without documentation. It's difficult enough for any emigrant to get a similar employment status than he or she had in their home country unless they pocess a qualifacation recognised and certified in the country that the migrant is arriving in.

Commerce is commerce, capitalism is capitalism. Whether the emigrant's lot improves in the short term can depend on their atttitude towards the work too..many may just see is as temporary work used to pay for some food and accomadation - a stepping stone onto something else.

However there are provisions in the UK to prevent some of these abuses taking place...there is both a national minimum wage which is legally binding on the employer and a recommended London Living Wage