Weak Deterrence: What Lies Behind the Rising Iranian Activities on British Soil?

The facts reveal that Iran continues to rely on human cells to carry out security operations in its favor within the UK, highlighting the increasing concerns in the United Kingdom over "rise in Tehran-backed hostile activity."

In a complex security operation, British police on May 4, 2025, arrested eight individuals, including seven Iranian nationals, in two separate investigations into “terrorism.”

The Greatest Threats

The Metropolitan Police said in a statement that, during one of the operations, five individuals were arrested, four of whom were Iranian, in connection with suspicion of a plot to target a specific location, which was not named.

The police added that the four men, aged between 29 and 46, were detained on suspicion of "preparing an act of terrorism" and remain in custody.

British Home Secretary Yvette Cooper described the arrests as part of two major operations, noting that they reflect some of the most significant threats facing nations and the counter-terrorism efforts witnessed in recent years.

The four Iranian men were arrested under the Terrorism Act, while the fifth man, whose nationality has not yet been disclosed, was detained under the Police and Criminal Evidence Act.

Dominic Murphy, head of the Counter Terrorism Unit at the Metropolitan Police, said, “This is a fast-moving investigation and we are working closely with those at the affected site to keep them updated. ”

"The investigation is still in its early stages, and we are exploring various lines of enquiry to establish any potential motivation as well as to identify whether there may be any further risk to the public linked to this matter."

Meanwhile, in a separate case, police arrested three individuals, all Iranian nationals, in an operation conducted by the Metropolitan Police's Counter Terrorism Unit.

The Metropolitan Police confirmed that the three arrests "are not connected to the arrest of the five individuals."

The men, aged 39, 44, and 55, were detained under the National Security Act of 2023, which grants police the authority to arrest individuals suspected of "involvement in activities threatening from a foreign power."

A report in the Daily Telegraph stated that British authorities believed they were dealing with an imminent attack during the arrests.

These detentions come amid growing concerns over Iranian activity on British soil.

Notably, in March 2025, Iran was listed as the first foreign power to be placed under the enhanced level of the Foreign Influence Registration Scheme (Firs), which aims to protect the UK from malign foreign influence. The system is set to come into effect in July.

This means that anyone directed by Iran to carry out activities in the UK must disclose this or face a prison sentence of up to five years.

The measures also imply that all individuals working within the UK on behalf of Iran or its intelligence services, including the Revolutionary Guard, will be required to register their activities or face imprisonment.

British security agencies had previously warned of the growing threat from "criminals" backed by Iran.

According to Ken McCallum, head of the UK’s domestic intelligence service (MI5), in October 2024, Tehran was behind one conspiracy after another in the UK. 

He revealed that five new attacks were planned in 2023, bringing the total number of foiled plots since January 2022 to 20.

McCallum added that officers are giving the utmost attention to any increase in "or broadening of – Iranian state aggression in the U.K."

‘Gray Zone’ Deterrence Policy

In this context, Dr. Alaa al-Saeed, an expert on Iranian affairs, told Al-Estiklal, “When Britain arrests seven Iranians in one go across two separate counter-terrorism operations, this is not merely a security issue or an isolated incident. It is a clear signal that Tehran is exporting its internal tensions and external suffocation to the capitals of the West. The Revolutionary Guard, whether through its institutions or its softer fronts, is no longer content with suppressing its own people or disciplining its neighbors. It has now extended its reach into the heart of Western democracies, using methods that are no longer hidden from intelligence agencies.”

"This systematic escalation by Iran against Britain, when understood through the lens of Iran’s new security doctrine, reveals that since the assassination of Qasem Soleimani, the former commander of the Quds Force, Iran has moved beyond direct military retaliation. Instead, it has started to redefine the rules of engagement in a more complex manner, with the emphasis being: strike in the most unexpected place, using unconventional methods, and under an unofficial cover," al-Saeed added.

"European capitals, with London at the forefront, have become a new theater for influence—not through tanks or missiles, but via sleeper cells, networks of influence, and attempts at intimidation and infiltration," he continued.

"For Tehran, Britain is not just another European country; it is the capital that has hosted some of the most prominent leaders of the Iranian opposition abroad, provided platforms for media outlets that expose the situation within, and sheltered figures who are seen in Tehran as symbols of doctrinal enmity, not just political opposition."

"From this perspective, London becomes a central target for Iran’s 'gray zone' deterrence strategy, through which Tehran aims to send a message to its exiled opponents: you are not safe, even in the heart of Western empires."

According to al-Saeed, "But the issue doesn't stop at opposition figures. After Tehran’s failure to secure significant gains from the nuclear negotiations, and following a series of setbacks in Iraq, Syria, Lebanon, and Yemen, the Iranian leadership—particularly the security establishment—realized that Western pressures were no longer only being directed from Washington and Israel. They were now being shaped and activated from London, Paris, and Berlin as well. To break this Western circle, Iran would need to pay a direct cost, deliver a real threat, and send firm messages in a language that brooks no ambiguity."

"This is why, in March 2025, Iran became the first country to be placed under the enhanced level of the Foreign Influence Registration Scheme in the UK. The decision was not precautionary, but rather proactive, based on extensive surveillance of suspicious activities, links to money laundering networks, and the use of cultural and religious institutions as fronts for illegal operations."

"But the more alarming aspect of this expansion is that it is no longer tied to the Israeli Mossad or the American CIA. It has become a purely European threat, one that British security agencies are keenly aware of."

"This is why when the British Home Secretary described the recent arrests as part of major operations, the term is significant. It points to the broader security context in the UK, used only when the threat is deep-rooted, far-reaching, and entangled within structures of influence, rather than isolated individuals," al-Saeed concluded.

Iranian nationals have previously targeted other Iranians residing in the UK.

In one instance, an independent television network, Iran International—which broadcasts in Persian and criticizes the Iranian government—moved from London to the United States after its journalists received state-backed threats, according to a 2023 report by the BBC.

In response, the British Foreign Office announced in January 2024 that the new sanctions imposed by both the UK and the U.S. on Tehran were a direct reaction to the threats against Iranian international journalists and Iranian exiles abroad.

The sanctions, according to the British Foreign Office, targeted Iranian officials linked to Unit 840 of the Revolutionary Guard, who were involved in a plot to assassinate Iran International broadcaster Fardad Farahzad and former channel presenter, Sima Sabet.

According to British broadcaster ITV, Iranian Revolutionary Guard spies offered a human trafficker $200,000 in October 2022 to assassinate Iran International broadcaster Fardad Farahzad and former channel presenter Sima Sabet. However, the hired assassin turned out to be a double agent and exposed the plot.

ITV reported that the original plan was to detonate a car bomb outside the Iran International office in London in the fall of 2023. 

However, due to the presence of security forces around the building, the plan was altered and replaced with a plot to kill Farahzad and Sabet.

According to the report, Iranian Revolutionary Guard spies told the individual they hired to kill Farahzad and Sabet that Iran International had severely insulted Iran in the media.

Additionally, in 2023, an Austrian national was convicted for carrying out a "hostile reconnaissance" operation against the headquarters of Iran International in London.

The following year, a British-Iranian journalist working for Iran International was stabbed in London.

In February 2025, a UK court sentenced a former British soldier to 14 years in prison for spying on behalf of Iran, after he triggered a manhunt following his escape from prison before his trial.

A judge at Woolwich Crown Court in southeast London stated that Daniel Khalife, 23, had attempted to execute a "dangerous and far-fetched plan" to pass sensitive information to Iranian intelligence in exchange for money.

The former soldier, whose mother is Iranian, had gathered information over a span of two and a half years while working in both the UK and the U.S., including the names of elite special forces personnel, before his arrest and subsequent charges in 2023.

Rising Tension

In this context, Taher Abu Nidal Ahwazi, a member of the political bureau of the Democratic Popular Front for the Liberation of Ahvaz—an opposition group to the Iranian regime—told Al-Estiklal, "Iran has intensified its activities in Britain due to rising tensions with the West, its efforts to target opposition figures, and its use of espionage and indirect influence tactics. This also comes in response to British policies hostile to Iran, taking advantage of Europe's previous weakness in deterrence."

Ahwazi added that Iranian activities against London are rooted in "the presence of an active Iranian opposition in the UK. Iran focuses on targeting its opponents abroad, particularly activists and organizations opposing the regime, some of whom operate from within Britain, making the country a prime target for espionage operations or assassination attempts."

"Iran employs asymmetric warfare, relying on unconventional tools such as cyber infiltrations, media influence, and local agents to extend its reach or destabilize its adversaries. Britain is part of this battleground."

He argued that Iran is responding to London’s policies that support its enemies, noting, "Britain backs or hosts regional powers hostile to the Iranian regime, which makes it a target for Tehran's soft and hard tactics."

"The leniency shown by European countries towards previous Iranian actions encouraged Tehran to push further, and we can call this a failure of deterrence against Iran in the past. This is why we’ve seen some governments, like the British, start taking stricter measures, such as their inclusion in the Foreign Influence Registration Scheme," Ahwazi concluded.

Iran has repeatedly rejected insinuations that it is behind conspiracies to target the United Kingdom.

In October 2024, Iranian Foreign Ministry spokesman Ismail Baghaei accused the UK of hosting terrorist groups that promote violence.