I'm surprised there's such a debate as I would've thought it's pretty clear that British families should be given priority.
I believe that families who's been paying taxes and living in the community all their lives should have priority over families who've decided to move to the UK and can't actually get their own accommodation. If people decide to come to the UK, they should be able to support themselves. If they can't support themselves, then it's their problem for not being sufficiently prepared beforehand.
(Let me say that I'm no BNP-supporter, I'm mixed race, and have grown up in 6 different countries.)