It was an uneven playing field for British workers, some jobs being done are not for modest wages, but are still large wages as you said in their native countries add to that some jobs were purposely targeting migrant workers, it was not that British workers would not do some of those jobs, that is a misperception created by the media, some of those jobs were advertised abroad, it was only the public facing jobs that were offered to British workers, any Brits that went for the employed migrant jobs were not even given an interview, and British field workers were laid off and replaced by migrant workers. The only area I can think of that migrant workers actually deserved the role more than their British counterparts was in catering but then again when you look at the hours and wage involved, it was more enticing for migrant workers.