Even the solitary UKIP MP, Douglas Carswell, denounced that poster on Question Time last night.

But the real drivers of xenophobia has to be recognised as being the drip drip effect of constant headlines in the Daily Express, Daily Mail and the Sun, building up an atmosphere in which the closet racists feel it's OK to come out into the open.
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One aspect of migration that seems to be ignored is that, so far as migrant workers in agriculture are concerned, this is largely a continuation of the tradition of such work being done by transient migrants from other poorer parts of the British Isles, rather than of people coming to settle in the country.

And an enormous proportion of other people who have come from Eastern Europe will tell you they have every hope of going home if and when circumstances allow, and long for that day. From most people from all countries emigrating is very much a second best forced on them by economic circumstances. In Ireland, for example, for many years it is common to see emigration as a plague. In bad times it builds to a flood, in good times it falls to a trickle.