London: Iran has executed a British-Iranian national who once served as its deputy defence minister, its judiciary reported on Saturday, defying calls from London for his release.

Alireza Akbari was handed the death sentence on charges of spying for Britain, which had declared the case against him as politically motivated.

“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.”

Late on Friday, Cleverly had said Iran must not follow through with the sentence - a call echoed by Washington.

The Iranian judiciary’s Mizan news agency reported the execution early on Saturday, without saying when it had taken place.

“Alireza Akbari, who was sentenced to death on charges of corruption on earth and extensive action against the country’s internal and external security through espionage for the British government’s intelligence service ... was executed,” Mizan said.