I can’t explain why, in the face of all the seductive images and lyrical descriptions of the new Tintagel footbridge, I’ve become fixated on a small incision slashed through the surface of the walkway in the middle of the bridge. I know it’s technically the meeting point between the two cantilevered segments, a 40 mm expansion joint in an impeccably engineered structure. But it struck me forcibly that the seemingly reassuring surface connecting clifftop to clifftop, strung in tension over the dizzying void below, had been cut. It gave me a nervous charge. Was this an actual moment of the sublime?