The former foreign secretary Jeremy Hunt said he supports extending the United Nations (UN) arms embargo on Iran, which is set to expire in October this year.
In April, the US circulated a draft UN resolution that would indefinitely extend the embargo.
Speaking at a Henry Jackson Society virtual event on Friday, Mr Hunt said he supported extending the embargo.
Mr Hunt was hosting the webinar focused on the Joint Comprehensive Plan of Action (JCPOA), more commonly known as the Iran nuclear deal, with guest speaker Brian Hook, the US special representative for Iran and senior adviser to the Secretary of State Mike Pompeo.
“I wholeheartedly agree we have to find a way of extending the arms embargo,” he said.
“I think there is a twinge of irony in the US wanting to extend an embargo on a deal that it itself has withdrawn from, and used the mechanisms of the JCPOA to do that.
“But I think the real point is that nobody can afford to allow Iran to go back to buying arms, I’m sure you’ll get full support from the UK on that, and I hope you get it internationally.”
A UN Security Council resolution that endorsed the 2015 nuclear deal between Tehran and world powers envisages an end to the embargo five years after the deal.
President Donald Trump pulled America out of the deal in 2018 and imposed harsher sanctions on Iran.
Mr Hunt was asked whether the UK Government would follow the footsteps of the US in designating the Islamic Revolutionary Guard Corps (IRGC), a branch of the Iranian Armed Forces, as a terrorist organisation.
Mr Hunt replied: “Because the IRGC effectively controls the Iranian regime, I don’t have any doubts at all that they are sponsoring terrorism all over the region and that’s what we have to stop.
“And I think the diplomatic calculation is if you designate that organisation are you sending a signal to the Iranian regime that you want regime change, and therefore ultimately making an agreement less likely going forward?
“It’s a very finely balanced judgment and I couldn’t predict whether that judgment on the UK side might change or not under my successor.”
In April, the UK Foreign Office condemned reports that Iran carried out a satellite launch in violation of international sanctions, amid rising tensions in the Gulf.
Pressure is also mounting on Iran to grant clemency to British-Iranian Nazanin Zaghari-Ratcliffe, who was handed a prison sentence after being accused of plotting to overthrow the Iranian government, which she has denied.