The real pleasure of the place, however, is that walking up the steps and pushing open the door is like entering the wardrobe into Narnia. Behind the rational 18th-century exterior is a vortex that spreads, sprawls and expands, rising up into the clouds, spiralling down into the bowels, edging back to the beyond.
Readers are sucked down the 15 miles of cool iron corridor and swallowed by layer upon layer of shelving. You breathe in leather and dust, you blink as fluorescent lights flicker. You could be lost for a week and as happy as a skylark.
This, and other sections, are housed on metal grids which allow you to look upwards and downwards to other floors. For the critic Raymond Mortimer, gazing through ‘the half-transparent floors of the book-stack, I feel inside the brain of mankind’.