His characterising of the use of nuclear weapons as "murder" is deeply offensive. He is basically saying that members of the Trident submarine force are potential murderers, as well as former members of the V Force, the tactical strike force in Germany etc. That is a view you may choose to hold when addressing a CND meeting with a silly hat on, but not when you are seeking to become prime minister.
Fortunately as today's vote showed, he has no more chance of becoming the next PM than I have.