Protecting systems, applications and data hosted on a Cloud environment against cyber-threats, and accounting for security incidents across the Cloud estate are prerequisites to Cloud adoption by business, and a fundamental element of both national and corporate cyber-security and Cloud strategies. Yet, Cloud IaaS and PaaS providers typically hold Cloud consumers accountable for protecting their applications, while Cloud users often find that protecting their proprietary system, application and data stacks on public or hybrid Cloud environments can be complex, expensive and time-consuming. In this paper we describe a novel Cloud-based security management solution that empowers Cloud consumers to protect their systems, applications and data in the Cloud, whilst also improving the control and visibility of their Cloud security operations. This is achieved by enhancing the security policy management of commercial technologies, and via their integration with multiple Cloud-based hosts and applications. The result of this integration is then offered as a re-usable service across multiple Cloud platforms through a Cloud service store.