The husband of British woman who is in prison in Iran has said he is disappointed in the failure of Boris Johnson's efforts two years on from her arrest.

Nazanin Zaghari-Ratcliffe, a British-Iranian dual citizen, is serving a five-year prison sentence after being convicted of spying charges.

Richard Ratcliffe said the battle to set his wife free has become a "test of endurance", particularly after the Foreign Secretary's unsuccessful bids to secure her release.

Mrs Zaghari-Ratcliffe, who was arrested in 2016, denies the charges and maintains she was in Iran to introduce her young daughter Gabriella to her parents.

Ahead of the second anniversary of her detention, Mr Ratcliffe said: "We didn't expect to be needing to mark this anniversary - not after the hopes of Christmas and the Foreign Secretary's word.

"But it remains a cold late Spring. Nazanin was told that if she wasn't home by Christmas, at least it should be done by Nowruz, and we should worry if we go past March 2018, with the storms that might lie ahead. And now we have."

He added: "Our story has become a test of endurance, and there is a need to recharge spirits - particularly after the disappointment of the Foreign Secretary's mission failing to deliver, and Nazanin becoming caught up in this government stand off - so we wanted the anniversary to be an occasion where we drew positive energy."

The key question is whether Mr Johnson has "given up on his promise to bring home Nazanin soon", the Free Nazanin campaign said.

Mr Ratcliffe and his supporters have requested to meet Mr Johnson with lawyers present, to ask what are Nazanin's rights in his view as the stand off continues.

Tulip Siddiq, Ms Zaghari-Ratcliffe's MP, has said if Boris Johnson cannot secure her release "it is time that the Prime Minister stepped in".

A Foreign Office spokeswoman said: "On the second anniversary of Nazanin's arrest we continue to approach her case, and all of our British-Iranian consular cases, in a way that we judge is most likely to secure the outcome we all want.

"Therefore we will not be providing a running commentary on every twist and turn.