MPS are to stage an inquiry into the detention and release from Iran of Nazanin Zaghari-Ratcliffe and Anoosheh Ashoori.

The Commons Foreign Committee said it would take evidence on how their cases were handled by British officials as part of a wider investigation into “state level hostage situations”.

Mrs Zaghari-Ratcliffe, whose sister-in-law Rebecca Ratcliffe is a GP in Cwmbran and who was detained for six years, and Mr Ashoori, who was held for almost five, were released last month after the UK agreed to settle a historic £400 million debt dating back to the 1970s.

Following their return both have been critical of the failure of the Foreign Office (FCDO) to secure their freedom sooner.

Announcing the inquiry, committee chairman Tom Tugendhat MP said their return was “long overdue” and that they were right to seek answers as to what happened.

He said that it was also important to look at the wider issues raised by Iran’s use of the detainees as leverage in the debt negotiations.

“Iran is not the only country engaging in state hostage taking,” he said.

“The tactic is fast becoming a tool of choice for authoritarian states and recent high-profile cases have highlighted the challenges governments face when securing the release of hostages held captive by states.

“This inquiry will examine the support provided by the FCDO to hostages in recent cases, as well as take a look at the broader picture and ask how the Government can clamp down on the practice internationally.”

The announcement of the inquiry was welcomed by Mrs Zaghari-Ratcliffe’s local MP, Tulip Siddiq, who was involved in the campaign for her release.

“While in Iran, Nazanin was blindfolded, handcuffed, interrogated and subjected to solitary confinement, sleep deprivation and torture,” she said.

“The Government has serious questions to answer about why this was allowed to happen to an innocent British citizen, who was caught as a pawn in a political dispute between two countries.”