IRNA � Iranian Ambassador to London in a message criticized the UK foreign secretary's stance against Tehran, saying de-escalating tensions needs major efforts.

"During Foreign Secy Hunt's tenure, the UK�s Iran policy was an abject failure; increasing tension and culminating in confrontation in the Persian Gulf after the UK's illegal confiscation of Iranian oil," Hamid Baeidinejad wrote on his Twitter account.

He added: "Major efforts needed to de-escalate, and to move toward better understanding."

"Mr. Hunt also wasn�t able to help Nazanin Zaghari Ratcliffe's release, as he confused his role as a diplomat with that of a politician whose rhetoric is designed to satisfy the public," he noted.

Iranian ambassador reiterated: "Had he continued the diplomacy his predecessor started, her case might�ve been resolved."

Nazanin Zaghari-Ratcliffe, who worked for the Thomson Reuters Foundation, was arrested in Kerman in April 2016 on charges related to national security; she has been sentenced to five years in jail. Though her husband had claimed that she has visited Iran to meet her family and had had no media missions, in November 2016, Boris Johnson, the then UK foreign secretary, said in a speech in the British House of Commons' Foreign Affairs Select Committee that she had been on media mission.