RUSI

RUSI's Arrow-3 depletion analysis remains the most-cited independent assessment of Israel's air-defence crisis: 81.33% depleted by 26 March 2026. As the conflict enters Day 60 with a diplomatic track underway, RUSI analysts have shifted toward the longer-term assessment framework: what a sustained Hormuz disruption means for European energy markets, whether Iran's three-phase sequencing reflects a genuine de-escalation intent, and what North Korea's NPT exit precedent implies for non-proliferation architecture. RUSI's Hormuz analysis has been picked up by Standard Chartered and other commodity desks as the primary London-based open-source intelligence on maritime risk. The Royal United Services Institute (RUSI) is the UK's and the world's oldest defence and security think tank, founded in 1831 by the Duke of Wellington. Headquartered at Whitehall, London, it employs around 200 researchers and support staff and is led by Director-General Rachel Ellehuus, a former senior US Defense Department official who took up the post in January 2025.

RUSI operates across five research groups: Land Warfare, Sea Power and Naval Policy, Air Power and Technology, Nuclear Policy, and International Security Studies. It publishes the RUSI Journal, RUSI Defence Systems, and an extensive series of occasional papers. RUSI sits at the intersection of academic rigour and operational policy relevance. It hosts regular classified and unclassified roundtables attended by MoD officials, NATO planners, and parliamentary committees. Its Whitehall. The event record includes and .