6.11 The Head Office has a critical role in enabling CDS and PUS to provide sound and timely advice to Ministers on current and potential operations, and in supporting CDS in his role as the military strategic commander. As set out in more detail in Part 10, we understand that the Head Office finds itself, as in other areas, drawn towards operational and tactical business that is properly the responsibility of PJHQ and deployed commanders. Our understanding is that the formal split of responsibilities between the Head Office and PJHQ is correct, but that it is not always followed. There would therefore be value in re- stating the respective roles of the Head Office, PJHQ, national deployed commanders and the single Services, and then ensuring they are consistently applied. This will help ensure these vital functions are performed effectively; it may also expose some duplication and thus scope for effiency.