Nazanin Zaghari-Ratcliffe has appeared in court in Iran and has been told she will face another trial on Sunday, an MP has said.

Iran’s state TV reported on Tuesday that the British-Iranian dual national was facing a new charge, citing an unnamed official.

Labour MP Tulip Siddiq later said she had spoken to Mrs Zaghari-Ratcliffe, confirming that she had appeared in court on Tuesday morning.

Ms Siddiq tweeted on Tuesday: “I’ve been in touch with Nazanin Zaghari-Ratcliffe and can confirm that she was taken to court this morning and told she will face another trial on Sunday.

“I know many people are concerned about her welfare and I’ll keep everyone updated when we have more information #FreeNazanin.”

The Hampstead and Kilburn MP also said: “This is an extremely worrying development, and I know many people are concerned about Nazanin’s welfare.

“The last four years have been excruciating for her husband Richard and her daughter Gabriella, who is growing up without a mother.

“The United Nations have recognised Nazanin’s imprisonment as arbitrary and unlawful, and any further court case is clearly unacceptable.”

A Foreign, Commonwealth & Development Office spokesperson said: “Iran bringing new charges against Nazanin Zaghari-Ratcliffe is indefensible and unacceptable.

“We have been consistently clear that she must not be returned to prison.”

Lisa Nandy MP, Labour’s shadow foreign secretary, said she found the news “deeply concerning”.

She said: “Reports that a trial could be held as early as Sunday suggest the prospect of her receiving a fair and legitimate hearing is unlikely.

“The UK government must now make urgent representations to the Iranian government and reiterate demands for her immediate release and safe return to the UK.

“For more than four years, Nazanin and her family have been forced to endure this living nightmare and our thoughts are with them during this incredibly difficult period.”

Former foreign secretary Jeremy Hunt tweeted: “This is hostage diplomacy and Iran needs to know that Britain will not stand for it.”

Amnesty International, which campaigns against human rights abuses worldwide, said the news was a “terrible blow” to her family and supporters.

Kate Allen, the organisation’s director, said: “Nazanin has already been convicted once after a deeply unfair trial, and there should be no question of her being put through that ordeal again.

“There have always been concerns that the Iranian authorities were playing cruel political games with Nazanin, and that looks to be the case here.

“As a matter of absolute urgency, the UK Government should make fresh representations on Nazanin’s behalf, seeking to have any suggestion of a second trial removed.”

Mrs Zaghari-Ratcliffe was granted temporary release from prison this spring following the coronavirus outbreak after serving nearly all of her sentence.

She was arrested at Tehran’s Imam Khomeini airport while travelling to show her young daughter, Gabriella, to her parents in April 2016.

She was sentenced to five years in prison over allegations, which she denies, of plotting to overthrow the Tehran government.

She was later afforded diplomatic protection by the UK Government, which argues that she is innocent and that her treatment by Iran failed to meet obligations under international law.

It has been claimed Mrs Zaghari-Ratcliffe is being held in order to force the UK into settling a multi-million pound dispute with Iran.

The debt dates back to the 1970s when the then-shah of Iran paid the UK £400 million for 1,500 Chieftain tanks.

After he was toppled in 1979, Britain refused to deliver the tanks to the new Islamic Republic and kept the money, despite British courts accepting it should be repaid.

Her husband Richard Ratcliffe said last month there was “clearly a stand-off” between the two countries, and that he feared his wife could face a second court case once her sentence comes to an end next spring.