Recent reviews of vocational qualifications in England have noted problems with their restricted nature. However, the underlying issue of how to conceptualise professional agency in curriculum design has not been properly addressed, either by the Richard or the Whitehead reviews. Drawing on comparative work in England and Europe it is argued that vocational and professional curriculum design requires a transparency tool in order to map out the various categories of professional agency and their relationships with each other that need to be taken account of in curriculum design. This tool is not prescriptive but illustrates critical choices that curriculum designers need to make. The categories of agency include: skill, transversal ability, project management and occupational capacity. The further categories of contingent and systematic knowledge are also described, as well as personal characteristics relevant to work (competences). The exercise reveals that certain important categories are not usually taken into account within the English context to the detriment of curriculum design. Some technical issues concerning vocational curriculum design and assessment, such as permeability, levelling, referencing and trust are then discussed.