The couple had argued a decade earlier when she sent the boy to a private Montessori nursery; he went along with it only because they couldn’t find a spot at a council-run facility. Her decision to enrol him at Queen Elizabeth’s grammar school in Barnet, nine miles from their home, was too much. The name of the school alone must have kept him awake at night. Characteristically, Mr Corbyn was at a peace conference in Holland when the news broke, and he returned to home to journalists camped out on his doorstep.