The unions were simply unable to leverage their large memberships for political effect. They are weak, and barely feature in England’s three-decade-long story of radical school reform. Opposition to reopening was also a particularly difficult stance to maintain. In August, Chris Whitty, England’s chief medical officer, announced that “the chances of children dying from COVID-19 are incredibly small,” whereas school closure “damages children in the long run.” By the summer, this way of thinking had hardened into a consensus: The opposition Labour Party supported reopening.

No surprise, then, that teachers ultimately fell into line. In late August, TeacherTapp, a teacher pollster, found that 71 percent of teachers said they were looking forward to going back, a higher percentage than in previous summers.

Serge Cefai, the executive head teacher at St. Thomas, looked puzzled when I asked whether the unions had given him trouble. Not at all. “We told [staff] we’re going to follow guidelines and we do … We’ve spent a huge amount of money trying to make sure that staff feel safe when they come into school.”