Iran's Foreign Ministry summoned British Ambassador to Tehran Hugo Shorter on Wednesday to protest London's designation of Iran's Islamic Revolutionary Guard Corps (IRGC) as a 'security threat' under the Counter-State Threats Act, warning that the decision would face an 'appropriate and decisive Iranian response'.

This move came one day after Britain summoned Iranian charge d'affaires Ali Nasim Far in London, over what the British government described as Iran's role in directing proxy groups to carry out attacks across Europe in recent months.

Britain announced on Monday the designation of Iran's Revolutionary Guards and a related group as 'security threats' under new powers aimed at preventing foreign states from employing proxies in surveillance and sabotage activities.

British Prime Minister Keir Starmer said the bill, to be introduced in Parliament this week, stipulates that 'anyone found to support or assist these groups will face up to 14 years in prison'.

The list of groups covered by the new legislation includes the 'Volunteer Corps' of Russian military intelligence and the Iran-linked 'Islamic Righteous Movement', which has claimed responsibility for attacks targeting Jewish interests in London.

The legislation grants the British government powers similar to those used in banning terrorist organizations, allowing it to designate agents of foreign states who pose a threat to British national security.