When King Charles addresses the United States Congress tomorrow, he should chide President Trump’s administration for intending to back Argentina’s claim to the Falkland Islands.

Unfortunately he won’t. No 10 wouldn’t let him. There will be warm words about the enduring transatlantic relationship. American lawmakers will doubtless give the King a friendly hearing.

But it’s surely clear that the Trump administration no longer regards Britain with fondness. The idea, set out in a leaked memo, that the US should side with Argentina over the Falklands is shocking. The President wants to punish this country for not joining his misconceived war in Iran.

Even if Trump disowns the memo, the damage has been done. Argentina, which is psychotically obsessed with acquiring the Falkland Islands, can see that it has America’s tacit support.

Actually, it has long suspected as much. After the Argentinian fascist junta invaded the Falklands in April 1982, the Reagan administration sat on the fence for several weeks, trying to broker a deal that would have been favourable to Argentina.

It was only after the Government, magnificently led by Margaret Thatcher, despatched a formidable naval task force that President Reagan decided to back Britain. He was ideologically and temperamentally attuned to the British Prime Minister. The same can’t be said of Trump and Starmer.

By contrast, the increasingly unstable occupant of the White House lavishes praise on Javier Milei, the libertarian, populist President of Argentina, who responds in kind. Milei is fixated on obtaining the Falklands, and demanded talks with Britain following the leak.

What will the Lion of Downing Street, Sir Keir Starmer, now do? The Falklands don’t rank high on his list of priorities, particularly when this unloved lion is lame, and menaced by aggressive lions and lionesses.

True, the PM has boasted in the past that an uncle of his was on a warship torpedoed during the Falklands War. (In fact it was bombed.) It must also be conceded that No 10 responded robustly to the disclosure of the leak, saying that control of the islands is ‘not in question’.

Still, the fact remains that whenever Sir Keir Starmer looks at a map of the world, and spots a few far-flung British islands marked in red, his immediate instinct is to get rid of them.

This is what he did with the Chagos Islands. Although they are legally British, he gave them to Mauritius, and agreed to pay £35 billion for the privilege of leasing Diego Garcia, one of the islands, for 99 years. Trump has put a stop to this nonsense, at least for the time being.

Starmer was advised by Attorney General Lord Hermer during this process. We may speculate that, since the Falklands were acquired as uninhabited islands during the heyday of the British Empire, Hermer is eager to hand them to Argentina, which at its nearest point is 300 miles away.

If this Government truly cared about the Falklands, it wouldn’t have allowed their defences to be reduced to such a risible level, though admittedly it was the Tories who started the rot.

We now have a grand total of four Typhoon jets there, plus a patrol boat. The Ministry of Defence recently removed a Voyager refuelling aircraft, which will reduce the scope of the Typhoons to provide round-the-clock air cover at times of crisis.

Such paltry defences are unlikely to deter Argentina, which is refurbishing 24 F-16 jets bought from Denmark, while seeking to procure two KC-135R Stratotankers from the US for air-to- air refuelling.

The task force sent by Margaret Thatcher more than four decades ago comprised two aircraft carriers, assault ships, destroyers, frigates, submarines, dozens of fighter jets and bombers, and 26,000 men. Even then it was touch and go to recover the islands.

Nowadays the Royal Navy is so depleted that ministers struggled to find a single warship to send to the Mediterranean after Trump started bombing Iran. Eventually HMS Dragon set sail, only to limp into port at the earliest opportunity.

We do have two new aircraft carriers but one of these, and sometimes both, can usually be found in port rather than on the high seas, either being refitted or repaired.

President Milei (who, ironically, is an admirer of Thatcher’s economic policies) looks at Starmer and sees a weak man. If he studies prospective usurper Angela Rayner, he may wonder whether she knows where the Falklands are. The thought of Andy Burnham probably makes him chuckle.

The truth is that the Falkland Islands and their 3,600 inhabitants (99.8 per cent of whom have said they want to remain British) can’t be defended at the moment. The Argentine government knows it. Starmer knows it. Even Trump knows it.

It is not just Starmer’s fault. For years our Armed Forces have been recklessly run down. The cash-starved Ministry of Defence has long put the Falklands on the back burner, in the hope the Argentinians won’t try to invade them again.

But what if it becomes plain – as it has – that the United States won’t kick up a fuss should the Argentinians decide to reverse the humiliation of 1982, and take what they misguidedly believe is theirs?

Asking Starmer to do the right thing may be academic since he could be bundled out of No 10 very soon. But whoever is the Labour prime minister over the next three years should wake up to the appalling danger of a second Argentinian invasion.

It goes without saying that National Security Adviser Jonathan Powell and other Labour figures would join Hermer in cheerfully raising the white flag to hand over the Falkland Islands as soon as possible, ideally with a present of a few million pounds.

But this Government couldn’t get away with a sell-out of that magnitude. It would never be forgiven for thrusting thousands of British citizens into the doubtful care of the Argentinian government, or for rendering futile the sacrifice of 255 British servicemen in the war of 1982.

This is not a problem that can be negotiated away, as Starmer, Hermer and Powell have tried to do with the Chagos Islands, leaving the much-abused British taxpayer picking up an enormous bill.

The only way forward is to deploy enough military assets in the Falklands to convince the Argentinians that an invasion would not be the walkover they currently assume – with good reason – that it would be.

More aircraft and ships are needed, in and around the islands. Instead of flying the flag in the South China Sea, where they can have little impact, our aircraft carriers should make an occasional visit to the south Atlantic, if they can find their way out of port.

By the way, there are considerable oil reserves around the Falkland Islands that have been barely tapped. These should not be supinely ceded to Argentina.

The Falklands have been owned and administered by Britain for nearly 200 years – longer if you take account of a previous landing. People who regard themselves as British as you or me live there.

To lose the islands in another invasion would be an unforgivable betrayal of our fellow citizens, and a national humiliation from which it would take this country years to recover.