One could almost hear the spluttering. From Vauxhall Cross to Wellington, from Tel Aviv to Ottawa, spy chiefs across the world in Jordan, Saudi Arabia and Turkey spitting their coffee, whiskey and mint tea across their tables the moment news came to them.

Donald Trump had finally done it. He'd boasted to Russia. Russia! And revealed intelligence provided from another nation for US "eyes only".

He allegedly gave away top secret details of a plot against airlines using laptop bombs hatched by Islamic State to Sergei Lavrov, Russia's foreign minister, and Sergei Kislyak, the Kremlin's envoy to Washington.

According to the New York Times and the Washington Post, Trump also discussed military operations to disrupt the plot and gave away the location of where it was put together.

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HR McMaster, the White House national security adviser who was present at the meeting, insisted that "at no time were any intelligence sources or methods discussed, and no military operations were disclosed that were not already known publicly".


He insisted the Post's story was "false" - but the national security adviser's denial was very much a non-denial.

It has been followed by Trump himself admitting he shared information about "terrorism and airline flight safety".

The President may not have revealed the actual source of the intelligence. Nor the methods used to penetrate the plot to blow up airliners with bombs hidden in laptops. But what he did reveal could get agents killed.

Russia is a rival power. It has forces on the ground on the opposite side of the Syrian civil war to the US which has been backing some rebel groups fighting the Kremlin's ally Bashar al Assad.

An intelligence source or operator on the ground effective enough to penetrate IS risks being killed or compromised by Russia.

Spying at this level is a foul business. Trump's failure to understand how he has soiled the waters dangerously is staggering.

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Israel has already warned its US ally that it felt the White House under Trump may not be trustworthy in dealing with the most sensitive data.

That view is shared in Europe, through the Five Eyes intelligence sharing community of the UK, US, Canada, New Zealand and Australia.

Blurting the details he is alleged to have spilled would have been bad enough had he done so in a meeting with a Five Eyes nation. It would have signalled immaturity and incompetence.

But boasting to the Russians the day after he fired James Comey as head of the FBI, an organisation that continues to investigate whether there have been links between the Trump presidential campaign and the Kremlin, signals something more sinister.

A US president cannot be prosecuted for breaking secrecy rules because he has the power to declassify anything.

But America's intelligence allies will be wondering why on earth he felt the need to share another nation's super secret information with Russia.

Many members of NATO in the Baltics, in Poland and elsewhere in Eastern Europe are in a state of heightened anxiety over a Russia which they think - and western intelligence services agree - now poses a greater threat to regional peace than any time since the end of the Cold War, and perhaps even further back.

In that context Trump's revelations have done the sort of blow to western intelligence that Russian spooks could only fantasise about.

He has sowed doubt, real doubt, among America's allies that his White House can be trusted to keep shared secrets secret.