The task was straightforward: allow the United States to utilize two military bases located on UK soil. That was all.

One base is situated in England (RAF Fairford in Gloucestershire) and the other in the Indian Ocean (Diego Garcia). Nothing more was required.

There was no pressure on Britain to participate in the US-Israeli military actions against Iran. Realistically, the UK currently has limited military resources to contribute. The Americans can manage without us.

Furthermore, the UK wasn’t even asked to publicly endorse or express enthusiasm for the operation, unlike the center-left governments of Canada and Australia, which had both shown support.

All that was sought was access to two bases deemed crucial, or at least important, for the success of America’s mission to challenge the regime in Tehran.

Yet, Sir Keir Starmer hesitated to approve this seemingly straightforward request.

He consulted his learned friend and attorney general, Richard Hermer, who told him it would be illegal under international law. No surprise there: that’s the advice you expect when you appoint a Left-wing international law obsessive to such a pivotal position.

Despite the high stakes, the Prime Minister (who sees himself as something of a legal brain in his own right) didn’t attempt to question it. Or seek other legal advice, even though there are plenty of well- regarded, experienced lawyers who don’t agree with Hermer.

Why would he? Hermer’s advice fitted with Starmer’s world view of the primacy of international law, which is why he was made attorney general.

International law may be an opaque, malleable, even mysterious construct with controversial rulings involving judges sometimes appointed by dictators. But when it comes to a choice between international law and the national interest, Starmer chooses international law every time. Request denied, the Americans were told.

Cue the biggest crisis in Anglo-American relations of modern times.

Donald Trump lashed out at Starmer from the Oval Office on Tuesday. He lumped Britain with the viscerally anti-American socialist government of Spain. He painted us as far worse even than the usually US-sceptic French. Nowhere near as good as the Germans, whose Chancellor was sitting beside him, offering no words in Starmer’s defence. So much for all that cosying up to Europe.

Now you don’t have to agree with everything Trump said – far from it – to recognise Starmer had made a grave error. He’d caused a serious rupture in transatlantic relations for the sake of stopping America from using two bases on our sovereign territory, over which we have control.

Donald Trump lashed out at Sir Keir Starmer from the Oval Office on Tuesday after the PM couldn’t bring himself to allow America to use two US military bases on UK territory

Request denied, the Americans were told. Cue the biggest crisis in Anglo-American relations of modern times

It was especially stupid to pick a fight with our most important ally at a time of great global peril, with the UK more than ever depending massively on the US for our safety and security, given how successive governments, Tory and Labour, have hollowed out our own military these past 20 years.

A proper leader would have been unequivocal in putting the national interest first and granted America, as a friend and ally, the use of our bases, even while insisting, if that was the chosen policy, we had no intention of joining the US and Israel in their assault on Iran ourselves.

The two positions are entirely consistent and defensible. After all, Margaret Thatcher managed it when Ronald Reagan asked for permission to use British bases from which to launch a bombing raid on Colonel Gadaffi’s Libya in 1986. But Starmer, of course, is no Thatcher.

The true folly of his decision was revealed within 24 hours. Iran’s immediate response to the first wave of US/Israeli airstrikes was to pummel the Gulf States to its south with missiles and drones. These countries are our allies as well as America’s. Hundreds of thousands of British citizens live and holiday in them.

It was a foreseeable Iranian response. I recall discussing the prospect, should a hot war with Iran break out, with British diplomats and Emirati leaders in Abu Dhabi 15 years ago. But it clearly hadn’t occurred to the great legal minds around the PM.

They quickly executed a remarkable legal reverse ferret: since British interests and citizens were now at risk it was OK after all for America to use our bases. With one caveat: our bases could only be used for defensive purposes.

Thus did Britain’s posturing in one of the most significant events of our era enter the theatre of the absurd.

Exactly how will Britain determine if US aircraft taking off from Diego Garcia for Iran are carrying ‘defensive’ or ‘offensive’ bombs? If they hit missiles sites targeting the Gulf States is that ‘defensive’? If they hit the Revolutionary Guard quarters masterminding the missiles is that offensive?

The lawyers, of course, have not explained. Neither has Starmer. My interrogation of various Labour apologists has proved entirely fruitless. Just to ask the questions is to illustrate the distinction is as ridiculous as it is unworkable. Trump will obviously (and rightly) ignore it.

But it is now British policy. With the practised professionalism of a man who’s done it many times before, Starmer performed yet another U-turn. What was illegal on Saturday morning became perfectly acceptable by close of play Sunday. At a stroke, Britain had become both an embarrassment and an irrelevance.

This is Starmer’s signal achievement. It’s what happens when you outsource military and defence policy to lawyers ignorant of both.

Nobody in Washington – or in the major European capitals for that matter – much cares what Britain says or does now in relation to Iran.

I have been inundated by queries from US friends, most of them far from fans of Trump, asking if Britain has lost its marbles. Sadly, there is only one answer.

Great damage has been done to US-UK relations for no purpose or benefit. It might not be terminal. You never know with Trump if he’s going to bear a grudge forever or forget about it next week. But I fear this rift will not be easily patched up. I’m not even sure Starmer will attempt it.

Starmer is fighting yet again to save his political skin.

Labour was thumped in last week’s south Manchester by-election and is heading for further ignominy in English, Welsh and Scottish elections on May 7. Two-thirds of Labour MPs and at least half the cabinet are facing the political knacker’s yard come the next election on their party’s current performance.

So the mood is to ditch him, if only they could agree a successor. What can Starmer do?

It will not have passed his attention that being seen to be at odds with Trump is popular with the Labour faithful and its media cheerleaders in a way that Starmer- the-Trump-Whisperer was not. So why not keep the standoff with Trump going?

Starmer has already despatched Labour MPs and spinners onto the airwaves to imply that he didn’t just knock back Trump when it came to the bases. He also defied US requests for the UK to join in the attacks on Iran. This is a downright lie. America has made no such request.

Starmer is clearly desperate. But if a more fractious relation with the US is what it takes to keep his job, so be it.

Labour is now in the grip of its anti-American, anti-Trump soft-Left. Starmer needs to pander to these forces – and to the pro-Palestinian Muslim vote – if he’s to hold on to his job. Since he’s an opportunist politician of no principle, I expect him to do so. The rift with Trump has come at a convenient moment.

Of course, the potential cost to the country – militarily, economically, diplomatically – of a prolonged transatlantic rift could be catastrophic.

It was always clear Labour’s Leftward drift would be bad news for the economy. But it could be even worse for foreign policy and defence.

Starmer once boasted that as PM he’d always put country before party. The risk now is he’s going to put himself before both.