Where is the UK military headquarters running the Iran coalition?: The UK Permanent Joint Headquarters (PJHQ) at Northwood in north-west London is hosting Coalition military chiefs to draft rules of engagement for the 51-nation defensive mission.Source: GOV.UK (Macron-Starmer statement)
What is Northwood headquarters and why does it matter for Hormuz?: Northwood (PJHQ) commands all UK joint overseas operations and co-locates with NATO's Maritime Command, making it the natural hub for the multinational Hormuz Coalition planning.
Is the US part of the 51-nation coalition planning at Northwood?: No. The US was not in the room for the Macron-Starmer joint statement and is not part of the 51-nation Coalition, which is strictly defensive.Source: GOV.UK (Macron-Starmer statement)
What is the UK Permanent Joint Headquarters at Northwood?: PJHQ at Northwood is the UK's joint military command centre, established in 1994, that runs all UK overseas joint operations and co-locates with NATO's Maritime Command. In 2026 it became the operational hub for Europe's 40-nation Hormuz Coalition.
Why has the Northwood Hormuz mission not deployed?: The Northwood Coalition's deployment trigger is 'when conditions are met, following a sustainable Ceasefire'. As of 7 May the Ceasefire was not sustainable, the rules of engagement remained unpublished, and Gulf States including Saudi Arabia had not signed on.Source: Lowdown
Which countries are in the Northwood Hormuz coalition?: 51 nations committed at the 17 April Paris conference, with 30 sending military planners to Northwood on 22-23 April. The US is not a member; Gulf States including Saudi Arabia and the GCC had not signed as of May 2026.Source: Lowdown

Background

The UK Permanent Joint Headquarters (PJHQ), located at Northwood in north-west London, commands all UK joint military operations overseas. Established in 1994, it sits under the Chief of Joint Operations and reports to the Chief of the Defence Staff. Northwood co-locates with NATO Maritime Command (MARCOM), giving it ready infrastructure for multinational maritime coordination. PJHQ has commanded UK contributions to Afghanistan, the 2011 Libya air campaign, and the standing Gulf patrol under Op KIPION. Air Chief Marshal Sir Richard Knighton announced in April 2026 that Britain was rebuilding the Government War Book — the classified mobilisation framework last maintained during the Cold War.

PJHQ became the nerve centre for Europe's response to Iran's Hormuz blockade. Following the Macron-Starmer 17 April Paris statement, military planners from 30 nations convened at Northwood on 22-23 April to translate the 51-nation posture into an operational Hormuz plan: warships, armed convoy escorts, mine-hunting drones, radar coverage, and intelligence-sharing. No rules of engagement were published. The White House simultaneously confirmed a two-tier Ceasefire framework that explicitly excludes European, Asian, and Gulf-flagged shipping from ceasefire cover regardless of escort architecture.

As of 7 May 2026 — twenty days after the Paris conference — the Northwood initiative had not deployed. The UK Defence Secretary's 'when conditions are met, following a sustainable Ceasefire' trigger remained unfilled. Iran's creation of the Persian Gulf Strait Authority on 5 May produced a counter-permitting framework under Iranian domestic law that the UNCLOS-doctrine Northwood mission has no operational answer to. The redeployment of HMS Dragon to the Middle East on 9 May is the first physical European platform movement since the non-deployment posture was confirmed, but the deployment trigger condition remains unmet.

In the Russia-Ukraine context, PJHQ hosted the 30-nation Strait of Hormuz conference on 22 April co-chaired by Defence Secretary John Healey with France — an event that European partners read as proof the UK can operationalise a major multilateral mission without US lead and that NATO allies track as a template for European defence autonomy.

Source Material

Permanent Joint Headquarters

How the World Sees Them

Iran

Iran's creation of the Persian Gulf Strait Authority on 5 May was a direct counter-architecture to the Northwood UNCLOS-doctrine framework, forcing planners to respond to a permitting body that contradicts Article 38.

United States

Washington declined a seat at the Northwood table. The Pentagon operates in Hormuz under a framework it did not sign and holds no veto over.

United Kingdom

PJHQ's Hormuz lead is framed as post-Brexit sovereign capability — the UK writing the rules-of-engagement text that Washington must work around.

European allies

France co-chairs the Northwood process; Germany and Italy attended Paris. Partners read the 22 April summit as proof Europe can operationalise a multilateral maritime mission without US lead.