Labour’s national executive committee, which is dominated by Sir Keir’s supporters, must give permission for a directly elected mayor to seek selection to be an MP. That discretion is now being presented as an obstacle course, with cost, a potential mayoral byelection and gender balance rules being thrown in Mr Burnham’s way. It is true that there is a chance Labour could lose the Manchester mayoralty if he were to stand down. But that underscores the message that the decision to block him is already made; the reasons can be assembled later.