Nazanin Zaghari-Ratcliffe's return to her family in West Hampstead could be delayed by new negotiations over the Iran nuclear deal, her husband fears.

It is now more than five years since Nazanin was first arrested in Tehran's airport, about to return from a holiday to visit her parents with the her then-infant daughter Gabriella.

She served a five-year sentence following claims by Iran that she had plotted to topple the government, claims she always denied.

The 42-year-old was once again summoned to court, in front of Judge Abolqasem Salavati, on March 14 and faced a twenty minute hearing, where she was briefly able to speak in her own defence.

Despite being told she would hear a verdict within seven working days, Nazanin is still waiting.

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Richard Ratcliffe said this week he is "decidedly pessimistic about the wisdom of the government's approach" and disappointed that - with nuclear negotiations proceeding - treatment of innocent people detained in Iran has not been a key part of discussions.

He said: "I think it was a real strategic mistake not to make the release of all the hostages a precondition of negotiations to revive the JCPOA (Joint Comprehensive Plan of Action) nuclear deal, and the failure to do so risks making us all bargaining chips in the middle of the nuclear negotiations."

There is also another hearing on the longstanding £400m debt the UK owes Iran set for April 20 - and Richard thinks that could be the sticking point holding up a verdict.

Ham & High: Nazanin Zaghari-Ratcliffe with husband Richard Ratcliffe and daughter Gabriella. Picture: RICHARD RATCLIFFENazanin Zaghari-Ratcliffe with husband Richard Ratcliffe and daughter Gabriella. Picture: RICHARD RATCLIFFE (Image: Archant)

He said: "My instinct though is that we won’t get a verdict until after things are clarified on the IMS case scheduled for 20 April.

"And if we are unlucky we will be held as leverage while the JCPOA negotiations continue."

Nazanin is not the only UK citizen being held as leverage in Iran - south Londoner Anoosheh Ashoori turned 67 in Evin prison earlier this month. Amnesty International used his birthday to reiterate their criticism that, in cases like Nazanin's and Anoosheh's, the UK government "hasn’t done as much as it should have done on behalf of its nationals who are being mistreated in Iran".

A Foreign, Commonwealth and Developement Office (FCDO) spokesperson said it was "doing all we can to help Nazanin and other dual nationals arbitrarily detained in Iran".

They added: "[Nazanin] must be allowed to return to her family in the UK without further delay.”