The British military have embarked on a comprehensive process of transformation towards a network-enabled, effects-orientated, and expeditionary force posture. This has involved developing brand new military doctrine, organizational concepts, and technology. The US military are also transforming, and American military ideas about network-centric and effects-based warfare have influenced the British military. But the British have not simply aped their US ally. Rather, British military transformation has followed a different path. Hence, this article proposes a dynamic model of military innovation involving two international drivers: new operational challenges and military emulation; and three national shapers: resource constraints, domestic politics and military culture. This model is then applied to a detailed empirical analysis of the process and progress of British military transformation.