Mrs Zaghari-Ratcliffe could have to wait a week before hearing a court’s verdict on new charges of “propaganda against Iran”.
She completed a five-year sentence earlier this month in Tehran on spying charges levied by Iranian authorities, the last year of which was spent under house arrest due to the pandemic.
But she returned to court on Sunday where she was tried on new charges of “propaganda against Iran”, her MP Tulip Siddiq said.
Some observers have linked Mrs Zaghari-Ratcliffe’s case to a long-standing debt Iran alleges it is owed by the UK.
Mr Raab said: “It is unacceptable and unjustifiable that Iran has chosen to continue with this second, wholly arbitrary, case against Nazanin Zaghari-Ratcliffe.
“The Iranian government has deliberately put her through a cruel and inhumane ordeal.
“Nazanin must be allowed to return to her family in the UK without further delay. We continue to do all we can to support her.”
Ms Siddiq, the MP for Hampstead and Kilburn, wrote on Twitter: “I can confirm that Nazanin appeared in court this morning and was tried on new charges of ‘propaganda against Iran’.
“No verdict was given but it should be delivered within a week.”
Sunday’s hearing, which lasted just over 20 minutes, was a continuation of the trial that was adjourned in November, on charges originally brought in 2017.
No new accusations were made and the charity worker’s lawyer was allowed to provide her defence, her husband Richard Ratcliffe said.
Mrs Zaghari-Ratcliffe made a personal statement in the court, where she clarified she did not accept the charge and highlighted the accusations and evidence were already part of her trial in 2016.
She was told this was the final hearing and to expect a verdict within seven working days.
After the hearing, Mr Ratcliffe said his wife’s future was still uncertain, facing open-ended detention, but that she was “relieved” it was her last trial.
He told the PA news agency: “I think the judge saying this is the last trial is just a nice feeling – I think it is a bit like you’ve done an exam, it was horrible, you don’t know whether you passed or not, but at least it is done and there’s just a relief that comes with that.
“And she’s done that and she’s gone off out for lunch with her mum and her sister which she hasn’t been able to do for a long time.”
Mr Ratcliffe said he was feeling “better than I was expecting” but was still “guarded, cautious and worried”.
“I thought there was every chance that they would drag this out over a number of court cases,” he said.
He added that he expected his wife to be convicted but did not know what sentence she would receive.
Mr Ratcliffe also criticised the British Embassy for declining the family’s request to accompany Mrs Zaghari-Ratcliffe to the court.
The Foreign, Commonwealth and Development Office said it had formally requested access to the hearing.
Speaking after the trial, Rupert Skilbeck, director of human rights group Redress said: “We have grave concerns that Nazanin could be returned to Evin prison or house arrest.
“This keeps her in a constant state of fear and uncertainty, and prolongs the severe psychological and physical suffering she has endured as a result of her torture and ill-treatment in Iran.”