The reality that I see (and I deal with payroll and HR) is that many businesses would struggle really hard to exist were it not for the agencies who provide European labour on short term no-commitment contracts.
Thats not to say that the employee does not have a commitment from the agency, they do most of the time, but it also often suits that labour to be flexible about the hours they work and to be able to move on at any time.
The workplace has changed dramatically over the past ten years - I recall a large plant grower towards the east of this country taking on Eastern European labour ten/twelve years ago from an agency that we did business with, that agency in turn relied on gang masters from various former soviet bloc countries who literally were like the Mafia, most of the labour they supplied were non-English speaking, record keeping was rudimentary, cash was king and eventually they didn't need us to record anything about the sites at all - that agency eventually walked away from those contracts because what was going on was blatently illegal.
It isn't like that now (thankfully).
The problem is that most stories in the written media feature very minority cases of fraud and corruption (like it used to be) and then portray that as the norm, when the truth is that eastern european labour is not cheap for the employer, but it is very flexible, which is a major requirement - when did you ever see or hear of that being emphasised in a documentary ?
An example of poor quality written media reporting - check how many immigrants there have been from Romania and Bulgaria since Jan 1st, or how many additional flights and buses have been arriving here - then look back at what was being speculated and lied about in the newspapers back in December and wonder why they haven't bothered with the story since.