This paper critically examines attempts to conceptualise the use of military intervention on humanitarian grounds, with a focus on the ‘responsibility to protect’ framework, and offers discussion of the way forward in light of the Afghanistan and Iraq wars and the US-led ‘war on terror’. It traces the history of the concept from its post-Cold War origins through to the UN World Summit of September 2005. The paper concludes with a brief review of the challenges that face the international community in moving forward, and the specific contributions that might be made by the UK government.