Bringing a new trial against Nazanin Zaghari-Ratcliffe is “indefensible and unacceptable”, 10 Downing Street said on Wednesday.

Nazanin was summoned to the office of the Iranian judge who has overseen her previous trials a day earlier and told she will face a second trial this Sunday.

Richard Ratcliffe has described the “claustrophobia and panic” Nazanin felt as she was summoned to see Judge Salavati,

Now the Prime Minister’s official spokesman has slammed the move, saying: “Iran’s decision to bring new charges against Nazanin is indefensible and unacceptable.

“We’ve been consistently clear that she must not be returned to prison, to do so would be unjust and inhumane.

“We are continuing to support Nazanin and her family at this very distressing time.

READ MORE: New trial for Nazanin is ‘illegal’ says husband Richard Ratcliffe“We are seeking to be allowed to attend the hearing that does take place, and we’re raising our concern about Nazanin’s case with the Iranian government at the highest levels.”

Advocacy organisation Redress, who fight for justice for victims of torture said there were clear concerns about the fairness of any trial.

The charity’s legal officer Leanna Burnard said: “There is no legal basis for Nazanin’s ongoing imprisonment. The revival of a second court case signals a clear intention on the part of Iran to hold Nazanin as a political pawn and threatens to prolong her suffering indefinitely.”

She also called on the government to assert its right to see Nazanin and to have access to the trial. Redress have represented Nazanin’s family in a legal capacity over the past four years.

Nazanin’s is the only case in Iran for which a March order granting clemency has not been implemented,

Richard said the trial would hear charges of spreading anti-government propaganda, in a case officials dropped in December 2017, after a visit from the then-foreign secretary Boris Johnson, but reopened in May 2018.

He added earlier this week: “We were expecting to be released in the spring when Nazanin came out of Evin, and other Westerners came home, but then we got stuck waiting. Events have escalated in the past week, though Iran has for a while been signalling displeasure.

“Behind closed doors we have been warning the government of the need to protect Nazanin and the others much more publicly, or this ordeal would spiral more.” Nazanin has served more than four years of a five year sentence imposed after she was convicted of spying offences, which she has always denied.

Local MP Tulip Siddiq called for “an urgent intervention by the UK government” after the news broke.