The Iranian ambassador has been summoned to the Foreign Office in response to three Iranian nationals being charged with spying offences under the National Security Act.
A Foreign Office spokesman said: "Today, upon instruction from the Foreign Secretary, the Ambassador of the Islamic Republic of Iran to the United Kingdom was summoned to the Foreign, Commonwealth and Development Office. His Excellency Seyed Ali Mousavi was summoned in response to three Iranian nationals charged under the National Security Act.
"The UK Government is clear that protecting national security remains our top priority and Iran must be held accountable for its actions.
"The summons follows this weekend's announcement which stated that three Iranian nationals had been charged with engaging in conduct likely to assist a foreign intelligence service."
Mostafa Sepahvand, 39, Farhad Javadi Manesh, 44, and Shapoor Qalehali Khani Noori, 55, appeared at Westminster Magistrates Court on Saturday.
The three men all arrived in the UK by irregular means, including by small boats and a lorry, between 2016 and 2022.
Sepahvand, of St John’s Wood, Manesh, of Kensal Rise, and Noori, of Ealing, spoke through a Farsi interpreter at the brief court hearing to confirm their names, dates of birth and addresses.
No pleas were entered by the trio who were all wearing grey sweatshirts, with Sepahvand attending in a wheelchair and Noori hobbling into the dock.
They are all charged with engaging in conduct likely to assist the Iranian foreign intelligence service between August 14 2024 and February 16 2025.
Sepahvand is also charged with engaging in surveillance, reconnaissance and open-source research, intending to commit acts, namely serious violence against a person in the UK.
Manesh and Noori are further charged with engaging in surveillance and reconnaissance, with the intention that acts, namely serious violence against a person in the UK, would be committed by others.
The trio were remanded into custody and will next appear for a preliminary hearing at the Old Bailey on June 6.
The three men were arrested on May 3, and five Iranian nationals were also arrested on that day in connection with an entirely separate investigation.
Iran's state-run news agency IRNA reported that Tehran said the detention was a violation of international law and politically motivated.
The Government will strengthen national security powers after the three men were charged, the Home Secretary said.
