To speak out as a leftwing Jew on any aspect of this century-old conflict is to risk isolation and hate from both sides. That much I know, having directed Jeremy Corbyn’s leadership campaigns and called out the antisemitism of that period. So, on 8 October, absorbing the emerging details of the Hamas massacre the previous day, I feared the consequence of speaking out again. It turned out that in such circumstances I could not have been in a more supportive place during the Labour party conference than at a joint-faith meeting organised by a Jewish and Muslim women’s group in...