I pictured the Green Book (which Rishi Sunak has been urged to tear up) as a matt card-bound thing like an exercise book at school (in which the staples might be rusty from storage). The thing now has a virtual existence. Engagingly subtitled ‘Appraisal and evaluation in central government’, it had been a real paperback book in its 2003 edition, with a picture of a lamppost and the London Eye on the cover.