Horizon, from Capita, is a web app to help NHS Managers and commissioners to model the demand for NHS resources and assess cost implications. It allows data to be uploaded, manipulated and visualised using a set of rich interactive tools.
Working closely with a lead UX Designer and .Net Developers I defined the visual look and feel of the UI Design and developed a living pattern library of front-end code.
We also used element collages, rather than the traditional mockups of every responsive template, to get client agreement on the design direction. I talk more about this kind of approach in my blog posts on systems-based design.