Who was to blame for Nazanin Zaghari-Ratcliffe being held captive in Iran? It shouldn’t take a professor of ethics to answer such a question. Mrs Zaghari-Ratcliffe was being held on trumped-up charges by a despotic regime that has used hostage-taking to advance its agenda ever since its formation in the Iranian revolution of 1979.

Back then it was said to be ‘students’ who spontaneously over-ran the US embassy in Tehran and took more than 50 hostages, holding them for more than a year while the new theocratic government ruthlessly exploited the situation to humiliate the US administration of Jimmy Carter. In the case of Mrs Zaghari-Ratcliffe, at least no pretence was made that anyone other than the government of Iran was behind her detention since spring 2016.

And yet according to Labour leader Keir Starmer, it was Boris Johnson’s big mouth that was to blame for her not being back in leafy Hampstead with her husband and daughter many moons earlier. ‘I’m sorry to say that the Prime Minister caused this to go on for longer because of his words,’ said Starmer.

The ‘words’ Starmer referred to are those uttered by Johnson during a select committee appearance in late 2017 when he was Foreign Secretary. At that appearance, Johnson referred to Mrs Zaghari-Ratcliffe as ‘simply teaching people journalism, as I understand it’. This was a blunder: the official position of the UK was that she had gone to Iran on holiday to visit relatives, unconnected to her work with the Thomson Reuters Foundation. Johnson’s regrettable slip was indeed noted by the Iranian authorities at the time and incorporated into their standard spiel about her detention.

But the idea that had Johnson not made that comment then Iran would have simply released its very useful pawn in the campaign to force Britain to settle a £400 million debt is ridiculous – as naïve and craven in its own way towards the regime of Iran as Jeremy Corbyn was towards Russia after the Salisbury poisonings.

One would have thought Starmer’s unwarranted dig at the Prime Minister would have set off a wave of criticism towards him. Particularly among the kind of high-minded Tory MPs who took umbrage on Starmer’s behalf when Johnson accused him of having failed to prosecute Jimmy Savile. But no, the Tugendhat and Ellwood brigade does not seem bothered when it is their own leader being ill-used.

Fortunately, some on the responsible left are not prepared to let Starmer’s smear go unanswered. The journalist and writer Phil Craig for one expertly dismantled the Labour leader’s case, saying:

I’ve been bringing myself around to support Starmer and it would be great to vote Labour with confidence again. But politicising a hostage? I made a Channel 4 series on the Beirut hostages and we interviewed the Iranian agents who were responsible.
The whole point is to transfer guilt from the perpetrators to the victims and their society so that division and rancour spreads amongst the ‘enemy’. Especially divisive arguments such as: ‘we’d release them if only x or y’. It’s cruel and it works. Starmer yesterday did exactly what the Iranians want.
Had Johnson not made his remark about training journalists there would have been some other pretext discovered to drag this agonising business out. Because that’s the point. And the leader of the opposition should not repeat the talking points of a murderous theocracy.

Foreign Office minister James Cleverly was equally clear about this, correctly remarking of the Iranian regime: ‘They did not need an excuse to do this. They have applied completely illegitimate charges to a number of people. I have no doubt his comments made no difference whatsoever.’

If he is not to be ranked alongside Corbyn and the other useful idiots of UK politics who inadvertently do the work of our enemies, Starmer should now withdraw his spurious claim. And for many grassroots Tory supporters, it would be nice to see the swollen ranks of their party’s junior grandees break a sweat to put pressure on him to do so. Or does the leader of the opposition get a free pass for any attack on the Prime Minister, no matter how ill-founded?