The designation creates a new criminal offence with up to 14 years in jail for those who support, assist or receive a benefit from the three state-linked organisations, while anyone carrying out espionage or sabotage on behalf of the groups could face life imprisonment.
Eagle described the measure as "akin to proscription but in the different context of a state".
"One cannot proscribe a state and suddenly announce it doesn't exist, but one can designate proxies that are acting on behalf of a state which gives police very similar powers," she said.
Eagle said the new power would "disrupt" the organisations and "those who support or fascinate them" by creating a new supporting offence.
The IMCR has claimed responsibility for seven attacks at UK locations linked to Jewish and Israeli communities, including the Hatzola ambulance attack.
Eagle said: "We all want to see antisemitism driven out of our country and this government has introduced support for the Jewish communities that have been threatened and directly targeted by IRGC proxies.”
Basij militants, wearing military uniforms, hold AK-47s and the flags of Hezbollah and Iran during a parade on January 10, 2025 (Getty Images)Middle East Images/AFP via Getty
Referring to the attack on the Hatzola ambulances in March, Labour MP Mark Sewards said the IRGC posed "a direct threat to the safety of the British Jewish community".
"We have seen synagogues and community centres firebombed and we have seen Jewish people stabbed on the street," he said.
Sewards, the Parliamentary chair of Labour Friends of Israel, also paid tribute to the departing prime minister, saying he was "eternally grateful" for Starmer's work to "transform the party" and "rid us of the poison of antisemitism".
The vote followed a Commons debate on Iran, during which MPs repeatedly highlighted the threat posed by Tehran and the IRGC.
Veterans Minister Calvin Bailey pointed to "more than 20 potentially lethal Iran-backed plots on British soil between October 2024 and October 2025, targeting journalists, dissidents and Jewish people living in this country".
"Britain treats that threat with the gravity it demands," he said.
The Leyton and Wanstead MP said Iran was among the hostile states "working to create division and manipulate young people, including those in my constituency".
Former veterans minister Al Carns warned of Iranian influence operations online.
He said: "Open-source media has highlighted that when the US and Israel struck Iran many months ago, a certain target was destroyed in Tehran. Overnight, a large proportion of Scottish independence media died, which underlines the point about division and protecting the right to self-determination and democracy in this country."
Shadow foreign secretary Wendy Morton asked: "What is Britain going to contribute to secure the reopening of the Strait?"
The Conservative MP said the conflict had exposed “uncomfortable truths for us at home.”
"Every threat to the Strait of Hormuz sends shockwaves through global energy markets; every escalation in the Gulf has consequences for British businesses and households; and every hostile state that we seek to deter requires us to have credible military capability that supports our diplomacy,” she said.
Describing Iran as a "terrorist regime" that has "exported antisemitism", Morton criticised Labour for taking two years to introduce measures against the IRGC despite promising action in opposition.
That prompted SNP Brendan O'Hara to tell her "not take the moral high ground when it comes to proscribing the IRGC", noting that the Conservatives had failed to ban the militia while in government.
Liberal Democrat James MacCleary condemned the war, saying it "was an illegal war started by a reckless and irresponsible President. Trump, together with Benjamin Netanyahu, led the US and Israel into this war without a plan. As a result, NATO is less secure and Trump has been humiliated by his arrogance."
O'Hara said it remained unclear "whether [the war] was Trump's choice or Netanyahu's", adding that he "suspects" that for many Iranians "freedom has never felt further away".
He criticised the US and Israel for having no "off ramp" to the conflict, arguing it was "harming the very people that Trump says he was acting to liberate" and had "given the regime in Iran huge strategic advantage" in the Strait of Hormuz.
"There is not a family in the UK who has not paid a direct price from Trump's behaviour," he said.
Responding for the government, Middle East minister Hamish Falconer said ministers recognised it must "balance the need to take firm action against the Iranian regime while also remaining diplomatic relations with it".
The measures were "in response to totally unacceptable behaviour", he said, adding: "We have to be absolutely clear that we wish to remain relations with Iran, but we will not accept attacks on our community."
Referring to the new designation powers, Falconer said MI5 had "been clear that this power is welcome and will give them additional power" alongside existing legislation under the National Security Act.
Earlier, during his final Prime Minister's Questions, Starmer pointed to his record on antisemitism in Labour: "I made a promise to rip antisemitism out of my party, and I did.”
He added: "Antisemitism and anti-Muslim hatred are a poison. We ripped antisemitism out of the Labour Party, and I've worked as prime minister to root it out of our country.
"And that's why, just this week, Mr Speaker, we invested a record £250 million to protect our Jewish communities, and we are using the new powers we introduced to designate the IRGC, going after those who incite violence on our streets."
