This includes ‘not only the acts of foreign enemies engaged in warfare within the realm or of subjects of the Crown engaged in internal warfare, but also the acts done by forces of the Crown in repelling the enemy or suppressing a rebellion. There must be something in the nature of warfare, something more in the nature of war or civil war than of riot or civil commotion. The risk is excluded in standard property insurance on the grounds that governmental authorities are responsible for law and order.