Britain on Saturday called the execution by Iran of British-Iranian national Alireza Akbari a barbaric act, and imposed sanctions on Iran's prosecutor general in response.
The Iranian judiciary's Mizan news agency had earlier reported the execution of the former Iranian deputy defence minister who had been sentenced to death on charges of spying for Britain.
Britain had said it should not follow through with the death penalty.
"I am appalled by the execution of British-Iranian citizen Alireza Akbari in Iran," British Prime Minister Rishi Sunak said on Twitter. "This was a callous and cowardly act, carried out by a barbaric regime with no respect for the human rights of their own people."
British Foreign Secretary James Cleverly also tweeted to say: "This barbaric act deserves condemnation in the strongest possible terms. This will not stand unchallenged."
Britain later said it had imposed an asset freeze and travel ban on Mohammad Jafar Montazeri, Iran's prosecutor general, "because he is and has been responsible for, engaging in, providing support for and promoting serious human rights violations in Iran".
"Sanctioning him today underlines our disgust at Alireza Akbari's execution," Cleverly said. "The Prosecutor General is at the heart of Iran's use of the death penalty. We're holding the regime to account for its appalling human rights violations."
(Reporting by Michael Holden, Editing by Angus MacSwan and Angus MacSwan)
