Tulip Siddiq, Labour MP for Hampstead and Kilburn, told a crowded hall of MPs that the law should be changed so dual-nationals abroad have greater protection.
Speaking at the debate she organised on “British Prisoners in Iran”, Ms Siddiq urged the government to proclaim Nazanin’s innocence.
West Hampstead mum Nazanin, 38, an Anglo-Iranian, has been held in Iran for 14 months, while her daughter, Gabriella, now three, is living with her grandparents in Iran.
Ms Siddiq described how there is increasing concern for Nazanin’s mental health.
At points the former Thomson Reuters charity worker has been suicidal.
Ms Siddiq urged the government to declare that Nazanin, and two other British-Iranian prisoners, Kamal Foroughi and Roya Nobakht, are innocent.
She said: “We would like to know if the government believes in the innocence and believes they should be returned.
“To say that these people are innocent and to ask for their release would send a very strong signal to the Iranian authorities.”
Ms Siddiq asked Conservative Foreign Minister Alistair Burt MP if the government could strengthen its law to better protect dual nationals when they go on holiday, adding that she would be putting forward a private member’s bill on this.
Ms Siddiq urged the government to consider taking breaches of the Vienna Convention, including arbitrary detention, to the International Court of Justice.
She pushed for the foreign office to meet with the Ratcliffe family.
Ms Siddiq said: “It’s something the families have raised with me over and again - why has the foreign secretary not met with them?”
Asked if she would consider working with other countries in the Middle East to help free Nazanin, she said: “This is a matter of life and death. We should be relying on any allies that we have, any friends that we have in the region.”
Alistair Burt MP said: “Like everyone else, I would like to see all those prisoners returned to their families and the UK.”
He said all the families have 24 hour access to consular officials and there is “no intention to keep anyone in the dark.”
Mr Burt explained that Iran does not recognise dual nationality and that under international law, states are not obliged to grant consular access to dual nationals.
While he said that the government’s current strategy was “based on decades of experience of working with Iran”, there is hope for improved relations, as a new embassy has opened.
He said: “We will continue to press for consular access.”
Mr Burt MP added: “The human rights situation in Iran remains dire.
“We are determined to keep holding the government to account.”
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