As Waterhouse has just observed, the mansion has an aerial or two. But Bletchley Park is a huge and ravenous spider that requires a web the size of a nation to feed it. He has seen enough evidence, from the black cables climbing the mansion’s walls and the smell and hiss of the massed teletypes, to know that the web is at least partly made of copper wires. Another piece of the web is made of rude stuff like concrete and asphalt.