The trees are waking up and underneath, amid the bracken and fallen leaves from last autumn, so is the forest. A spring morning, brisk and bright, with birdsong above, is the perfect moment to put on sturdy boots, pull on a cosy jumper and take a wander down to the woods. The leaves uncurl in the branches above, spreading their dappled green across the canopy, and on either side of the path, sudden and silent, an almost incomprehensible expanse of bluebells. Up close they are deep indigo, purple and lapis lazuli, with slender bells and curling edges, framed with lush green and brown earth. But at a distance, they haze into a cobalt sea that stretches into the distance around the ship-mast tree trunks that rise from the deep. A green sky and a blue floor – the world turned upside down for its annual spring spectacle.