Walking to the Commons last October, I noticed a man sitting on a chair outside the Foreign Office.

Curious, I walked over and recognised Richard Ratcliffe, whose wife, Nazanin, had spent six years in an Iranian jail for allegedly spying.

A resolute campaigner for her release, Richard had on this occasion resorted to a three-week hunger strike.

Little did either of us know then that Nazanin would be released four months later.

The raw emotion that we saw on television as she was reunited with her daughter Gabriella tore at the heartstrings of every parent.

I wept, unashamedly.

Nazanin’s release was just the tonic we needed in difficult times.

The fact it took five foreign secretaries and six years to achieve it merely underlines what a diplomatic feat it was.

Regrettably, Nazanin was a pawn in a complex power game.

Relations with Iran have long been fraught, most recently over their nuclear development programme, which they agreed to limit in a deal with the West in 2015.

Three years later, President Trump cancelled it, describing it as a ‘disaster’, reimposed sanctions and cited Israeli evidence that Iran was cheating by enriching uranium to weapons level.

Any hope for the release of hostages like Nazanin faded as Iran retaliated by hijacking Gulf shipping and funding terrorists who attacked Saudi oil installations and targets in the Middle East.

However, two weeks ago, nuclear talks restarted and an historic debt we owed to Iran was repaid.

Coincidentally, or not, Nazanin and a fellow inmate were released.

The Americans were unhappy that one of theirs was not and accused us of going solo.

Weaponizing diplomacy by taking hostages is Iran’s ugly trademark and, although Nazanin’s ordeal is over, others still languish in jail.