Family of Nazanin Zaghari-Ratcliffe protest outside Iranian embassy in London

Richard Ratcliffe prevented from handing over a petition demanding her return

Richard Ratcliffe, the husband of Nazanin Zaghari-Ratcliffe, with his daughter Gabriella pose for photographers during a protest outside the Iranian Embassy in London. EPA

Media surrounds Richard Ratcliffe outside of the Iranian Embassy. AFP

Richard Ratcliffe and his daughter Gabriella arrive to attend the protest. AFP

Richard Ratcliffe speaks to members of the media. AFP

People attend a protest in support of Nazanin Zaghari-Ratcliffe. AFP

Richard Ratcliffe holds a portrait of Nazanin Zaghari-Ratcliffe. Reuters

Richard Ratcliffe stands outside the Iranian Embassy as police look on. EPA

The husband of Nazanin Zaghari-Ratcliffe held a vigil outside the Iranian embassy on Monday to demand her release after completing her five-year jail term for plotting to overthrow the regime.

Ms Zaghari-Ratcliffe, 42, had her ankle tag removed on Sunday after spending the last year of her jail term under house arrest at her parents’ home in Tehran.

The Iranian authorities continue to hold her passport and have summoned her back to court on Sunday where she could face a new court ordeal that will extend her time in Iran. Her MP in the UK, Tulip Siddiq, has warned that the worst-case scenario is another five years in prison.

Richard Ratcliffe was prevented from handing over a 160,000-signature petition at the embassy in London on Monday after officials refused to meet him.

Mr Ratcliffe and his daughter Gabriella, 6, joined Amnesty International UK officials holding a large protest placard with the message “Free Nazanin” outside the embassy.

“Today marks a watershed,” Mr Ratcliffe said. “If you’d asked me when we first started campaigning with Amnesty to bring Nazanin home that five years later we’d still be knocking on the door of the Iranian Embassy, still waiting for them to ever open it and explain what’s going on, then I would have been horrified.

“It is such a gratuitous waste of human lives. Today it is hard to know just how much longer it will continue.”

A British-Iranian aid worker, Nazanin Zaghari-Ratcliffe, poses for a photo after she was released from house arrest in Tehran. Reuters

He told the BBC that other former hostages had told him at the end "it gets quite bumpy", but it felt like the saga was nearing a conclusion. "So fingers crossed it is but also we might have many more months to go," he said.

His wife was first held in April 2016 and spent most of the next five years inside Evin jail on what the UK says were trumped up charges.

Ms Zaghari-Ratcliffe – who worked for the charity arms of the BBC and Thomson Reuters media organisations – has always maintained that she was in Iran to visit her parents with her then baby daughter.

Campaigners say she was subjected to a grossly unfair trial, has suffered health problems and been forced to stay for months in solitary confinement.

Her family says that she is being used as a pawn in a broader diplomatic game connected to a decades-old £400 million ($553m) debt owed by Britain following the cancellation of an arms deal after the 1979 revolution. The UK was due to supply tanks to the Shah of Iran, but instead sold them to Iraq, while keeping payments from the deal.

Gabriella Ratcliffe, daughter of British-Iranian aid worker Nazanin Zaghari-Ratcliffe, protests outside the Iranian Embassy in London. Reuters

The UK accepts that it has to return the money, but the issue has been complicated by sanctions and the exact amount remains in dispute.

The British government has called for her immediate return to the UK. Prime Minister Boris Johnson said her continued confinement remains “totally unacceptable”.

“She must be released permanently, so she can return to her family in the UK, and we continue to do all we can to achieve this,” he wrote on Twitter.

Potential charges date back to 2017, but amount to little more than a “rehash of old allegations”, according to her family. They include attending a demonstration outside London’s embassy in 2009.

While in prison, the family said that the regime sought to recruit her to spy on a UK government department and media consultancy in return for her release. It was the final straw in a campaign of harassment that prompted Ms Zaghari-Ratcliffe to go on hunger strike. The offer was not repeated.

Kate Allen, director of Amnesty International UK, said: “Nazanin’s five-year jail sentence was a disgrace in the first place, but to apparently seek new means to hold her after the end of her sentence is cruelly rubbing salt into her wounds.”

“The UK now needs to act. We’ve been worried for a long time that the UK government was dragging its heels over Nazanin and other British nationals held in Iran.”