I agree that working illigally in UK is obligation especially for those Nepalese students who are deceived by educational consultancies in Nepal. BUT I don't agree that UK government used these students to boost UK economy. Lots of the colleges where  Nepalese students paid their fee are already closed and their owner ran away taking all Money. Most of the students are living either with another Nepali's house or sharing with other students (10-20 in 2-3 bed room house). Which benefits either house owner or a person who lead the house NOT government. In fact it makes lots of burden to govenment because government provides free health services to all these people. In some areas, local council can't clean up bins due to unexpected rise in number of people living in that area. So where is the benefit to government bringing these students in UK?? you may say, they have paid visa fee. Well everybody who enters UK pay visa fee. there are millions of people who enter UK every year.

If you really track where those money paid by students goes, then you can clearly see all of those money are gone to either another Nepalese' or Indians's or Pakistani's pocket illigally! So I don't think it's logical to blame government for those mistakes which are done by students by themselves.. ( but all these doesn't apply to those students who are studying in good colleges or universities!!!)