UK government questioned on Iranian debt on Nazanin's case
"We have never been granted sight of the judicial process or consular access to our dual British nationals detained in Iran," said James Cleverly, a junior minister at the Foreign Office.
"However, that has not stopped our ambassador in Tehran consistently pressing for her full and permanent release with senior Iranian interlocutors, most recently today, on 27 April," he added.
Cleverly said Prime Minister Boris Johnson had raised Zaghari-Ratcliffe's case with President Rouhani and that Foreign Secretary Dominic Raab had a "personal ongoing engagement" over the issue with his Iranian counterpart.
Read more: How America's 'maximum pressure' on Iran made China a winner
But Tulip Siddiq, a lawmaker who represents Zaghari-Ratcliffe's constituency in Parliament, slammed Johnson for failing to stand up for her constitutent.
She implied that Britain's failure to pay a 400 million pound ($530 million) debt to Tehran might be delaying her release.
"We cannot deny the fact that Nazanin was handed a fresh new sentence a week after the IMS (International Military Services) debt court hearing was delayed," Siddiq said.
Cleverly responded that Britain "does not and will never accept our dual nationals being used as diplomatic leverage."
The long-running debt dispute is over a sum the late Iranian Shah Mohammad Reza Pahlavi paid for Chieftain tanks that were never delivered, before the 1979 Islamic Revolution.