When did I say it had a negative effect? I said that you can't claim that the effect was purely due to the British as the situation in Russia and Poland had changed ever those years making some kind of Jewish exodus from those countries much more likely.
You seemed to be implying that. The situation in Russia had changed for the better as far as anti-semitism was concerned, the bolshevik revolution had a disproportionatly high number of jewish leaders due to the anti-semitism of the tsarist regime. The Balfour declaration was a response to this by the british in an attempt to distance the bolsheviks and the germans who were negotiating an armistice. Heres the wiki article on the balfour declaration I suggest you read it if you really do think the british took this up out of concern for the jews:
http://en.wikipedia.org/wiki/Balfour_Declaration%2C_1917Given the circumstances and reasons this was made you cant help but wonder if it might have contributed to german anti-semitism in some way.
And I notice you still haven't answered the most important question. What the hell should the British have done? Left the Jews to die in those countries?
I have, as I stated above the British put the biggest limits on Jewish immigration in 1939, at a time when anti-semitism was reaching its height in europe. I've given you a link to an article in which the british and the US agreed not to pressure each other into taking more refugees. It looks like leaving the jews to die in those countrys is exactly what the british did. They picked up the cause of a jewish homeland when it needed them the least and dropped it when it needed them the most. What the hell should they have done? Not ****ed people around for their own gain maybe?