Photo: Tom Morris, via Wikimedia Commons. File photo of the SIS Building in Vauxhall, London, not a photo of Sunday's announcement.
Iran's Foreign Ministry announced on Sunday, November 1, that it has designated Britain's Royal Navy and Royal Air Force as "terrorist organisations" and the country's foreign intelligence service, MI6, as a "hostile group" — a sharp escalation that drags London directly into the diplomatic crossfire of the ongoing US-Israeli war on Iran.
The measures, announced in a ministry statement carried by Iran's state-run IRNA news agency and the semi-official Tasnim news agency, took effect as soon as the statement was published on Sunday. They mark one of Tehran's most direct moves against a European power since the war began, and they landed on the same weekend that Iranian negotiators sat in Doha for a third day of talks with Qatari mediators aimed at ending the conflict.
What the designations mean
Under the announcement, MI6 — formally the Secret Intelligence Service (SIS) — is classified as a "hostile group" under Note 2 of Article 1 of Iran's law on intensifying punishment for espionage and cooperation with the Zionist regime and hostile countries. The ministry said the provisions of that law would henceforth apply to the British agency.
The Royal Navy and the Royal Air Force, meanwhile, were brought under Iran's law on countermeasures against the United States' designation of the Islamic Revolutionary Guard Corps (IRGC) as a terrorist organisation, and are "accordingly recognised as terrorist organisations" under Iranian legislation. The ministry did not say what the designations would mean in practice for British forces or personnel.
Why Tehran says it acted
Tehran framed the move as reciprocal. The ministry pointed to what it called Britain's hostile actions over the past year, including providing military bases, facilities and logistical support during the US-Israeli war against Iran, and London's decision on July 13, 2026, to place the IRGC under the United Kingdom's State Threats Act 2026.
News18 noted that the announcement also follows a security incident at RAF Fairford in England more than a month ago, which British Prime Minister Andy Burnham has said involved Iran, and the court appearance in London five days ago of two men charged under Britain's National Security Act in connection with that incident. Tehran has not publicly tied the designations to the Fairford case, and the ministry's statement cited Britain's broader actions rather than any single incident.
London rejects the move
Britain pushed back within hours. A UK Ministry of Defence spokesperson said: "We utterly reject this designation. The UK Armed Forces will continue to defend our people, personnel and interests, working closely with our allies and partners," according to Metro, as reported by Defense and Tech.
The exchange underlines how far the confrontation has widened beyond the US and Israel. Britain is not a combatant in the war, but its bases and facilities have been part of the regional military picture, and Tehran has now put London's armed forces and intelligence service on the same formal footing — in Iranian law — as the adversaries it is fighting.
Threats and talks, side by side
The designations arrived alongside a drumbeat of warnings. On Saturday, Iran's Supreme Leader, Ayatollah Mojtaba Khamenei, ordered the armed forces to be ready to answer any attack with an immediate response "without geographical limitations." On Sunday, Iran's defence minister warned that threats would not dictate how long any future war lasted, and an army spokesman said Washington would not be able to decide when or under what conditions a future conflict ended.
At the same time, the diplomatic track continues: Iranian negotiators were in Doha on Sunday for a third day of talks, and Tehran has been discussing a plan to reopen the Strait of Hormuz within two days if Washington meets its conditions. Whether the designations harden that negotiation or serve as leverage inside it is now one of the questions hanging over the coming week — with reports, covered separately on this blog, of possible US strikes on Iran after Tuesday's midterm elections.
Sources: IRNA, November 1, 2026; Gulf News, November 1, 2026; The Express Tribune, November 1, 2026; News18, November 1, 2026; The Tribune (India), November 1, 2026. The designations and Tehran's stated reasons are as given by Iran's Foreign Ministry; the UK response is as reported by Metro via Defense and Tech; the Fairford background is as reported by News18 and has not been confirmed by Tehran as a reason for the move.