For what it's worth, my two cents.
The poster is not about immigration. It shows refugees. Asylum seekers, if you will. Those fleeing rape, murder and torture and hellish wars.
There are international conventions that foresee civilised countries providing shelter to civilians in such circumstances. That didn't start with the EU. And let's hope, a majority doesn't believe it should end with the EU. So "take back control" from the EU not so relevant there.
Or maybe we are to believe that all - or even a majority of those depicted - are in fact economic migrants. That seems to be Farage's line. And if that's the case, then membership of the EU has never stopped the UK from applying whatever policy it likes. Australian points system anyone? Could be applied to non-EEA nationals from tomorrow as a fully paid up EU member. And let's not forget that more than half of the immigration to the UK falls into this category. Immigration that it is fully within the gift of Westminster to control.
But Farage never seems to mention that either. (And nor have his defenders here). But blaming Brussels is so much more convenient, it seems.
Finally, on the refugee crisis, could we hope that the EU would do more to help these poor unfortunates. That's what Scary seems to suggest, for example. What could the EU do to have more refugees treated humanely in more EU countries? Certainly, MSF and other NGOs would agree that the EU should take more refugees. Rather than trying to keep them in Turkey, for example.
But I don't think that's quite the failure that Nige has in mind. More to do with letting fewer refugees in than more.....
So at best, this poster is deceptive with regard to the debate about EU membership. And at worst, the clearest of dog whistles.