Summary: The EUMS is (in contrast to the MPCC) the non-operational military staff. A review of its directorate structures reveals it, in broad brush strokes, to be a military HQ (divided on traditional staff lines) pretending to be a Brussels DG, under the direct authority of the EU High Representative. Its head is a three star.
At stake: It is already becoming a strategic HQ in all but name, whose activities risk bypassing direct member state controls by presenting staffing faits accomplis.
What they say: “We strengthen the diplomatic leverage of the EU, because together with Member States we ensure that the EU can act militarily” – EUMS website
Exposure: The EUMS reportedly has around 250 staff. The current and anticipated UK proportion is unknown.
Action needed: MPs to verify current UK personnel numbers and in which staff branches they are; then push to withdraw posts in order to avoid duplication and undermining parallel planning structures at NATO.
Deep dive: https://www.eca.europa.eu/lists/ecadocuments/rew19_09/rew_eu-defence_en.pdf