In this paper we describe the evolution and development of the police.uk and data.police.uk sites, which publish open data about crime and justice in the UK, and make it accessible and comprehensible to the public. Police.uk has received over 64 million visits (754 million hits) since launching in January 2011. Open crime and justice data represents a key sector in the UK open data landscape, and citizens are keen to engage with the criminal justice system to become more informed about local levels of crime and other policing information. This paper sets out the policing context in the UK, discusses the journey in providing such open data, the processes involved and challenges encountered, and explores possible future developments.