The killing of Supreme Leader Ali Khamenei in joint US-Israeli strikes on February 28, 2026, has thrown the Islamic Republic into its most profound crisis since the 1979 revolution.
The eventual shape of the regime, whether it endures, fractures, or collapses, remains deeply uncertain. Leadership change in Iran could follow three primary trajectories: regime continuity, a military takeover or regime collapse. But across all plausible outcomes, short of total state failure, one institution is positioned to emerge strengthened: the IRGC. Analysts warn that the power vacuum could produce a more aggressive military leadership fuelled by nationalist fury, and the doctrine of “strategic patience” that Khamenei championed may give way to what one analyst has described as a “scorched earth” posture.
The appointment of Ahmad Vahidi as the new IRGC commander-in-chief, announced within hours of Khamenei's death, is itself a statement of intent. Vahidi was the founding commander of the Quds Force (QF), the very unit that a recent Labour Friends of Israel paper argues must be proscribed.
Vahidi is not simply a military figure; he is a man whose career traces the full arc of IRGC violence, from international terrorism to domestic repression. As interior minister from 2021 to 2024, the morality police under his command were responsible for the death of Mahsa Amini, and the US Treasury redesignated him in October 2022 for his oversight of all Law Enforcement Forces deployed to suppress the Woman, Life, Freedom protests, actions that resulted in thousands of deaths.
That the regime, in its hour of greatest peril, has turned to a man wanted by Interpol for terrorism and sanctioned for mass repression tells us everything about where Iran is heading. The case for proscribing the IRGC-QF does not weaken in the fog of war, it sharpens. If the IRGC consolidates further power in the post-Khamenei order, the UK will face not a weakened adversary open to diplomacy, but a militarised state whose new commander personally embodies the fusion of international terrorism and domestic atrocity.
To date, the UK response to January’s repression has consisted of condemnatory statements and incremental sanctions. The foreign secretary announced new sanctions targeting finance, energy and transport sectors and, last month, 10 individuals and Iran's Law Enforcement Forces were designated. These are not without value, but, in the face of an extraordinary rupture, they can all too easily be viewed as inadequate.
The UK’s longstanding position, that proscribing a state military body presents unique legal challenges, is frankly no longer tenable. The January massacres provide overwhelming evidence that the IRGC-QF meets terrorist designation thresholds through systematic civilian targeting, mass killings and coordinating crimes against humanity.
The government has a roadmap. The recommendations of Jonathan Hall KC's 2025 review created a state-analogous proscription mechanism specifically for entities like the IRGC. The government accepted these in principle, stating that legislation is a priority for “as soon as possible”. Given the threat posed by the IRGC to the UK – and the crimes it perpetrated against the Iranian people in January – this must become a matter of urgency, and the necessary parliamentary time must be found. The UK government must:
– Immediately proscribe the IRGC-QF under existing terrorism legislation. The IRGC’s Quds Force is formally designated by a number of allied governments, albeit as part of the wider proscription of the IRGC. This can be accomplished immediately without awaiting new legislation.
– Bring forward the state-analogous proscription legislation, as recommended by Hall, as an urgent priority with a clear timeline.
– Publicly recognise crimes against humanity. The foreign secretary should formally acknowledge evidence indicating crimes against humanity by Iranian security forces and support international accountability – including an ICC referral and a UN fact-finding mission.
– Enhance diaspora protection. Expand protective measures for British-Iranian dual nationals and dissidents by enforcing the new Foreign Influence Registration Scheme and strengthening security service cooperation with affected communities.
– Escalate and enforce sanctions. Target senior political elites, the IRGC and entities facilitating sanctions evasion, including cryptocurrency networks and oil smuggling.
– Identify and remove soft influence networks that advance the regime’s objectives under the cover of cultural, academic, charitable or media activity. This is not about restricting lawful speech, but about exposing opaque funding, coordination with sanctioned actors and systematic diaspora intimidation.
– Downgrade future diplomatic engagement. If the regime survives in some form, the UK must fundamentally recalibrate its diplomatic posture. Any future nuclear negotiations must not preclude accountability for mass atrocities.
The horrific events of early 2026 represent a watershed. Evidence points clearly to crimes against humanity executed by the IRGC-QF. The UK now faces a choice: treat this moment as another episode warranting condemnation and incremental sanctions, or recognise it as a qualitative rupture demanding a fundamental reassessment. The latter aligns policy with both moral reality and strategic necessity.
The line has been crossed. The threshold breached. The time for proscription is now.
Roger Macmillan is a counter-terrorism and security specialist and former director of security at Iran International TV
To get more from opinion, click here to sign up for our free Editor's Picks newsletter.