This is my husband. He has been a committed member of his Labour Party branch, a lot of his spare time has been spent working for the local party, and he was campaigning for a neighbouring council by-election right up to the moment he opened that email. This is as much about branch politics as anything, and I am very glad that it is blowing up in their faces. Recent health problems encouraged him to decided to resign rather than fight the suspension and he felt that even if he fought it, he has lost his trust in the other members of his branch who reported him rather than respect a difference of opinion. If you challenge a suspension, you are not supposed to talk about the reasons behind the suspension, and, he felt that this was something that needed to be talked about.
He says he is simultaneously euphoric at getting this off his chest, and heartbroken that his party has betrayed him.