Recent trends in immigration control have been on the face of it about 'deterrence' of would be migrants, and 'integration' of newcomers, but there has also been an unadvertised but sure-footed move towards privatisation which has wide implications and effects
it goes a long way; from extraterratorial ALOs - Airline Liaison Officers, who check passengers in country of origin and work with the check-in desks (imho a zone of extreme prejudice where your human rights are obscure at the discretion of an unoffical, untrained proxy border control/security force, wearing fancy airline livery free from legal scrutiny or responsibilty), the airlines themselves legally compelled to render tightly bound 'failed' migrants under guard from tax free legal limbo 'airside' to the hands of those they sought refuge from ...
... to the planned offshore detention centres, extrapolating UK force outside of it's legal constraints (
http://www.schnews.org.uk/archive/news682.htm ) no doubt sub-contracted to successive failed franchises of the international military-industrial complex, the private security who batter and racially abuse deportees without regulation or oversight (
http://www.medicaljustice.org.uk/ )
... into the world of work (as discussed above) where your employer, again untrained and unofficially, maintains internal migation controls,
... encroaching insidiously into the most personal and intimate relationships, uk has quite recently followed saudi to implement laws restricting marriage to foreigners without state authorisation, but it's much deeper than that, of course; potential partners require careful screening for possible advantage or detriment in the race for residence or a green card, power relationships overturn as legal status changes, dependency and exploitation is facilitated within communities, between partners, even parents and kids depending on who hold the right paperwork, so we're all immigration controllers
this last aspect of migration really interests me - how does the experience of a son of an immigrant man and a native woman differ from that of a daughter, or if the parents' origins reverse? thinking about inherited gender roles, access to different cultural stuff, different prejudices and discrimination suffered according to the family's ethnic shape...