During the blitz of 1940-41 the Houses of Parliament were damaged on 14 different occasions. The Palace of Westminster sustained particularly notable damage in Old Palace Yard and St Stephen's Porch. The worst damage, however, occurred on the final night of the air raids, the 10th-11th May 1941.
On that night the skies were clear, and the moonlight was bright. Over the course of almost 7 hours, 505 German bombers followed the path of the Thames to drop more than 700 tons of high explosive and 86,000 incendiaries across London. The raid led to the highest nightly casualty figure recorded: 1,364 killed and 1,616 seriously wounded.
The Houses of Parliament were hit with several incendiary bombs throughout the night, and fire took hold. As a fire in the Common's Chamber blazed, the roof the medieval Westminster Hall caught alight. The decision was taken to save the ancient Hall, and the Common's Chamber was destroyed. Four people lost their lives at Parliament that night.