Advice for those wishing to pursue a PhD in interdisciplinary design
Crucible is a network organisation, not a University department or research institute. Crucible has around 100 faculty members in Cambridge, all in different departments, and we quite regularly make arrangements to jointly supervise PhD students. (We also have several hundred more non-faculty members, who do not supervise PhD students).
However, one consequence of working this way is that we don't have a mechanism for processing applications for a programme in interdisciplinary design as such. Our students apply for PhD places via conventional disciplinary routes, but then develop a custom programme meeting their own needs and interests, often working closely with a single network member on an apprenticeship model, but sharing in that member of faculty's collaborations with other disciplines.
An important early step in developing an application for a PhD place is to identify a particular university department or faculty member where you would obtain your primary research training, and then work more closely with that person to develop an application for academic admission and potential funding. Typically, this would be a person and department in a field where you have demonstrated excellence as an undergraduate and/or master's student. Entry to Cambridge is extremely competitive, with the result that both funding competitions and allocation of academic places are dominated by students who already have substantial achievements in specific fields.
The Crucible core team - Alan Blackwell, David Good and Nathan Crilly - would be happy to give further advice, if it is unclear to you which department might be the most appropriate base for your research. It would be helpful if you could mention briefly the subject of your first degree, the nature of any professional/design experience, and your research qualifications (typically at Masters level).