The keepers of the 96m high clock tower say they have been monitoring the tilting closely since 1999. According to their figures, the process has been accelerating since 2003. While before it was moving at 0.65mm per year, now the rate is 0.9mm per year.
They claim that this will not be a problem any time soon: “Our resident expert believes it will be between 4000 and 10,000 years before it becomes a problem.” They don’t know what’s behind this acceleration, however, and say that there’s “no real proof what has caused it”. Current theories include the extension of the London’s subway Jubilee Line — which goes under the Parliament — and the clay ground on which the tower was built, which is now drying and may be causing the movement. [BBC News, Reuters]