The UK and the European Union are expected to coordinate moves to brand the Islamic Revolutionary Guards Corps (IRGC) as a terrorist organisation after the execution of Alireza Akbari, a British-Iranian dual national who was lured back to Iran by the security services three years ago. Akbari, who had been a senior defence figure in reformist governments nearly two decades ago, was hanged for being a spy for MI6, a charge his family deny. A friend of the family said “this is a murder case”, and vowed to prove the innocence of the 61-year-old, including allegations that he had been paid by British intelligence. Akbari leaves behind two daughters and a wife who lives in the UK. They had been given reason to hope for a last-minute reprieve, but his wife read of his execution on the Iranian state judicial news agency before dawn on Saturday morning. In the first of what is likely to be a series of steps, the British government imposed a travel ban and asset freeze on the Iranian prosecutor general, Mohammad Jafar Montazeri, described by the Foreign Office as “one of the most powerful figures in Iran’s judicial system”. The UK also summoned the Iranian chargé d’affaires while the British ambassador to Tehran, Stephen Shercliff, was in turn summoned by the Iranian foreign ministry for what was said to be an outrageous interference in the internal affairs of the Islamic Republic. Shercliff was told “the decisive action to protect the national security of the Islamic Republic of Iran will not depend on the consent of other governments, including England”. The Iranians claim Akbari was recruited by a previous British ambassador. The British calculation now will be whether to take further steps that risk the door being closed indefinitely on further talks over the stalled nuclear deal, or whether the danger of nuclear weapons proliferation in the Middle East is regarded as too great to antagonise the regime. Nuclear talks have been on hold for months with UN weapons inspectors denied access to Iran’s key sites. Without formally breaking off the talks, Western powers have said that while the repression of Iranian street protests continues, the nuclear deal is no longer their focus. Iran is thought to have enough enriched uranium to make a nuclear bomb, but cannot yet weaponise the material. A formal decision to proscribe the IRGC both in the UK and the EU is bound to lead to Iranian retaliation. The UK’s security minister, Tom Tugendhat, suggested the move was justifiable: “The state’s murder of another citizen shows the cruelty of the Iranian regime. The Iranian regime threatens other British citizens even in the UK, as MI5 head reported recently. We will defend our security.” The independent reviewer of terrorism legislation, Jonathan Hall, in a note last week warned that “proscribing a State entity under the Terrorism Act 2000 would depart from consistent and decades-long UK policy, and calls into question the definition of terrorism which, to date, has proven practical and effective”. He said the enduring policy of the government has been to treat terrorism by states as falling outside the Terrorism Act 2000, pointing out the Salisbury poisoning by Russian agents was treated as hostile state activity, not terrorism. But he added this appeared to be a policy position rather than a legal view on the interpretation of the Act, so giving UK ministers some flexibility to proscribe the IRGC if they wanted. In November, the MI5 director general, Ken McCallum, described the Islamic Republic as a “mounting concern. Iran projects threats to the UK directly, through its aggressive intelligence services. At its sharpest this includes ambitions to kidnap or even kill British or UK-based individuals perceived as enemies of the regime”. He went on to say that UK authorities have discovered at least 10 “potential threats” to “kidnap or even kill British or UK-based individuals perceived as enemies of the regime.” Akbari’s friends say he was the victim of a power struggle at the top of the regime, including efforts by some officials to oust the secretary of Iran’s Supreme National Security Council, Ali Shamkani. Akbari had been a key ally of Shamkani until 2005 when he left government. Responding to the execution, the British prime minister, Rishi Sunak, said: “I am appalled by the execution of British-Iranian citizen Alireza Akbari in Iran. This was a callous and cowardly act, carried out by a barbaric regime with no respect for the human rights of their own people.” The British foreign secretary, James Cleverly, added: “This barbaric act deserves condemnation in the strongest possible terms. This will not stand unchallenged.” Both the German foreign minister, Annalena Baerbock, and the French foreign minister, Catherine Colonna, issued statements of solidarity with the UK. Baerbock said: “The execution of Alireza Akbari is another inhumane act by the Iranian regime. We stand with our British friends and will continue to closely coordinate our action against the regime and our support for Iran’s people.” Colonna said: “Iran’s repeated violations of international law cannot go unanswered, especially when it comes to the treatment of the foreign nationals the country arbitrarily detains. France reiterates its steadfast opposition to the death penalty everywhere and in all circumstances, and condemns its political use in Iran.” It is expected the EU will impose sanctions on as many as 20 Iranian officials including the minister of sport, but Baerbock – under domestic pressure over the issue from the Christian Democrats – has also said the EU is looking at putting the IRGC on the terror list. EU lawyers are examining the evidential thresholds that have to be met to brand the IRGC as a terrorist organisation. The IRGC is already sanctioned in the UK, but some of those sanctions are due to be lifted this autumn as part of the nuclear deal.