In reply to Blizzard:
Sorry I haven't the thread, this might have already been explained - but the policy story over the past decade or so is as follows:
Economic boom (Labour):
- work permits given out easily
- low-skilled work schemes for agriculture mainly used by Eastern Europeans pre-accession
- high-skilled schemes to attract migrants with money and skills.
Accession (A8 - Poland etc - Labour):
- Economy still has stacks of vacancies, employers lobby govt not to impose controls to delay access to Labour market
- More Poles etc come the the UK than expected and the impact on services is noticed and criticised
- Maximum controls placed on Romania and Bulgaria
Economic bust (Labour):
- Policy doesn't really change
Economic bust (Tory):
- All economic migration from outside EU shut down
- Everyone complains because of EU migration and past policies which were response to economic conditions of the time
So, the only thing the govt can do now to reduce migration is leave the EU. You'll need to ask a load of economists whether the advantage of reducing migration is outweighed by the disadvantage of loss of access to the common market. No one knows for sure, but most sensible people think it is.
Put simply, govt policy on immigration is just a function of economics: when in a boom, you let people in, when there's a bust, you try to keep them out. The problem is that it's not really that simple, because once people are here their families will follow (we don't think it's right allow one person permission to live here but not their husband/wife/kids) and the idea of turning immigration on and off like a tap is a fallacy for many reasons I don't have time to explain.
It's an unwinnable policy area, in which everyone will moan whatever decision the govt make. Choke off growth in a boom so you don't have too many foreigners here in the bust? Not going to be popular. Leave the EU? Well it's gaining ground but it's hardly without drawbacks.