Country experiences long periods of drought after wet winters since last year. This is causing the porous rock beneath large parts of southeast England, including London, to move more than usual, cracking or tilting many of the city's historic houses in its most upscale neighborhoods. The damage has triggered the highest insurance payout in almost two decades, with experts warning it could get worse. London clay, the type of soil that covers most of these areas, is “quite unique” in that it can shrink and swell a lot, says Lee Jones, a geological engineer at the British Geological Survey who has studied Britain’s hazards for more than 30 years. “The wetter it is, the more it swells and expands, and the drier it is, the more it shrinks and cracks,” he said, adding that future temperature extremes will worsen the impact on buildings and roads.