- The debt dates back over 40 years to when the shah of Iran paid Britain £400 million for 1,500 Chieftain tanks.
LONDON: Tehran on Sunday abruptly postponed a new trial of British-Iranian woman Nazanin Zaghari-Ratcliffe, according to her husband, who accuses the Islamic republic of holding his wife as a pawn in a dispute with London.
"Yes, today's hearing was postponed," Richard Ratcliffe told AFP in London. Her Iranian lawyer was told "the case was not happening today", he added.
There was no immediate comment from Iranian authorities.
Britain's Foreign Office said: "We welcome the deferral of this groundless court hearing, and call on Iran to make Nazanin's release permanent so that she can return to her family in the UK."
Zaghari-Ratcliffe has spent more than four years in jail or under house arrest since being arrested in the Iranian capital in April 2016 while on a visit to see relatives with her young daughter.
Zaghari-Ratcliffe, who worked for the Thomson Reuters Foundation -- the media organisation's philanthropic arm -- denied charges of sedition but was convicted and jailed for five years.
Amnesty International UK accused Iran of "playing cruel political games" with Zaghari-Ratcliffe, and called on Britain to make it an "absolute priority" to get her home for Christmas.
She will turn 42 on Boxing Day, and was said by her British MP Tulip Siddiq to be "relieved, frustrated, stressed and angry" at Sunday's postponement.
"Once again she's being treated like a bargaining chip," Siddiq tweeted.
Zaghari-Ratcliffe has been on temporary release from Evin prison in Tehran and under house arrest since earlier this year because of the coronavirus pandemic.
Dashing hopes of a release soon, Iranian state media said on Tuesday that she and her lawyer had been notified of a new indictment, without giving further details of the charges or a trial date.
Ratcliffe had said last week that she was due to appear in court on Sunday, and that it was "increasingly clear" she was being held as a "hostage" against a longstanding UK debt to Iran.
The debt dates back over 40 years to when the shah of Iran paid Britain £400 million for 1,500 Chieftain tanks.
When the shah was ousted in 1979, Britain refused to deliver the tanks to the new Islamic republic but kept the money.
British Prime Minister Boris Johnson's spokesman said last week the government was raising concerns with Iran "at the highest levels", calling the new charges "indefensible and unacceptable".