Margot Parker MEP, UKIP's deputy chairperson, has described her imprisonment and treatment as heart-breaking.
Mrs Parker has long campaigned for the safe release of Mrs Zaghari-Ratcliffe, jailed for seven years in 2016 for 'spying', a charge she always denied. She was granted a three-day release last week to be with a four-year-old daughter and her parents. She was then taken back into custody and has suffered subsequent panic attacks.
Mrs Parker said:
"Whatever has been said or promised between the governments of the UK and Iran, this ongoing treatment of Mrs Zaghari-Ratcliffe is extremely cruel.
"We don't know what is going on behind the scenes but to separate her again from her daughter and family is shocking and proves the cruelty of the Iranian Government.
"It's nasty and there is no rationale behind it. I was praying she would at least be allowed to see out the remainder of her sentence with her relatives in Iran.
"To treat her in this way and again take her away from her daughter is saddening. Her husband has shown great dignity and it must be wretched to know of her alone in her darkest hour.
"The Government and campaigners must not rest until she is free - these are spurious charges and she must now be released permanently from jail."