I walk about the common with my imaginary medieval friend. "The ponds are so shallow. Why are they nearly dried out?" he says, amazed at the state of the grass. "What's happened to all the cowslips and buttercups - and the hay rattle flowers? Where are the clouds of butterflies that used to rise up before the scythe? "It's so quiet. Where are the voices of the children stone-picking in the fields, where is the birdsong, where are the grasshoppers?"