Building privacy, trust and security into the evolving digital ecosystem is broadly recognized as a key societal challenge. Regulatory activities in the US, Europe and Japan are complemented by industry initiatives that seek to rebalance "the crisis in trust" occasioned by widespread personal data harvesting. All parties agree that key to this challenge are increased accountability and control. Accountability not only seeks to strengthen compliance but also make the emerging ecosystem more transparent to consumers, while control seeks to empower consumers and provide them with the means of actively exercising choice. This proposal will develop the underlying technology infrastructure required to deliver both accountability and control. Although personal data management is generally considered an intensely personal matter, it is also inherently social: it is impractical to withdraw from all online activity simply to protect one's privacy. The success of the modern Internet and the "free" services it supports largely rests on the ability for advertisers and analytics providers to make money with the result that approaches that remove or diminish advertising revenues have been doomed to failure. The many motivations and uses for systems enabling personal management of personal data point to a need for tools enabling individuals to take more explicit control over the collection and usage of their data and the information inferred from their online activities, while addressing the challenges of HDI. Working with partner organisations we have refined our vision of just such a tool, a Databox, an on-demand personal data aggregation and query point, control over which rests directly with the user. The Databox vision is of an open-source personal networked device augmented by cloud-hosted services that collates, curates, and mediates access to our personal data. The Databox will enable and, in some cases, may even host third party applications and services that process personal data. The Databox will form the heart of an individual's personal data processing ecosystem, providing a platform for managing secure access to these data and enabling authorised third parties to provide the owner with authenticated services while roaming outside the home environment.