During the Civil War (1642-48), the Arundells were loyal to the king.
In May 1643, the castle was attacked by Sir Edward Hungerford, a Parliamentarian commander: and, after a short siege, the castle was surrendered to him.
In December, Henry Arundell led a Royalist counter-siege. Whether by design or misfortune, gunpowder mines laid in a drainage tunnel beneath the castle
produced an explosion powerful enough to cause a large part of the castle to collapse. The damage was deemed as beyond repair....