At that stage the UK had no reason to declare war on Germany other than our promise to Poland. We could have sat back and just watched things play out. Indeed H

At that stage the UK had no reason to declare war on Germany other than our promise to Poland. We could have sat back and just watched things play out. Indeed Hilter thought that we would do exactly that. (Bear in mind that there was not evidence of the holocaust for another 2 years. The huge (and real) moral basis of the European side of the second world war was largely discovered post facto.)