IT was French spy chief Jean-Marie Delarue who a few years ago hit the nail on the head about the problem of intelligence sharing. “In intelligence, one only has enemies, no friends”, he observed.

His words have taken on fresh resonance these last weeks, as the US has now managed to upset two of its closest allies and friends by allowing the disclosure of sensitive information.

First it was President Donald Trump’s leaking of intelligence from Israel relating to an Islamic State (IS) terror threat involving bombs planted inside laptop computers carried on airliners. Then over the last few days, Britain– unlike the Israelis – publicly voiced its anger with US government agencies after they leaked confidential details crucial to the investigation into the Manchester Arena attack. Yesterday Mr Trump promised to prosecute the “culprit” responsible for the Manchester leaks, which will throw his own “misdemeanour” into a curious place.

Both incidents, however, have highlighted concerns around the capacity for potentially jeopardising the trust of key information-sharing partners. They have raised questions, too, over just whose interests shared intelligence actually serves.

As the stark reminder in Manchester this week proved, Islamist-inspired terror networks think, co-operate and operate across borders, ignoring national boundaries. To use intelligence parlance, their threat is a “transnational” one.

If the latest reports from the respected online news portal, Middle East Eye are anything to go by, it’s not helpful of course that this very same transnational threat appears to have been exacerbated in recent years by the British government and security service MI5. Just yesterday the Eye reported that the UK, through MI5, operated what amounted to an “open door” policy that allowed Libyan exiles and British-Libyan citizens to join the 2011 uprising that toppled Muammar Gaddafi, even though some had been subject to counter-terrorism control orders.

It was with the opening up of this conduit that Salman Abedi, believed to be the bomber at the Manchester Arena, is understood to have spent time in Libya in 2011 and to have returned there on several subsequent occasions. In effect it would not be unfair to say that the Manchester attack is in part of Britain’s own making, insofar as such a policy created the power vacuum and instability in Libya after Gaddafi’s toppling that subsequently allowed jihadist terror to gain traction.

The news too that Mr Abedi flew from Turkey, a known transit point to IS territory, just days before the Manchester bombing only adds to these transnational concerns, given that he was known to the British security services.

Hardly surprising, then, that the question on many people’s lips right now is that if terrorists can so easily cross international borders – with or without MI5 help – why shouldn’t intelligence?

Unfortunately, with the long-established rules of the intelligence game, things has never been that simple in the spook’s world. Spies are a self-centred lot by inclination. Most have always cared more about their own secrets than someone else’s.

First and foremost among their rules is the control principle. As Sir John Sawers, former head of MI6 once made clear: “The service who first obtains the intelligence has the right to control how it is used, who else it can be shared with, and what action can be taken on it. It’s rule No. 1 of intelligence sharing”.

Add to this rule other even more basic hurdles such as national pride and bureaucratic turf rivalries, and you get some idea of why intelligence sharing is not as straightforward as might be expected.

In France alone there are up to 33 different agencies not all of them always pulling on the same rope, as was evident during the response to some of the recent terrorist attacks in the country.

Yet despite all these obstacles, intelligence sharing remains utterly crucial if the fight against transnational Islamist- inspired terror is to be curtailed and contained. It might stick in the craw of many that Britain’s security services are to some extent outsourced to Donald Trump’s America, but the reality is that even with the risk of leaks, shared intelligence is pivotal in the UK’s “special relationship”. Mr Trump might have exposed intelligence activities, sources and put agents lives at risk, but countries like Israel, Britain and others will just have to bite that bullet.

In intelligence gathering terms at least, the UK needs the US more than the US need the UK. The very idea that our Government Communications Headquarters (GCHQ) is some kind of equivalent to the US National Security Agency (NSA) is laughable. The launch last year of the European Counter Terrorism Ccntre, which sits within Europol, was a welcome development, but it has yet to find its feet.

Given too that Britain is about to leave the European fold, the UK will have to tread carefully over whom it relies on for its intelligence sharing partnerships. We will be even further removed from the sources of data and intelligence of our nearest neighbours. One would hope for example that data bases, like the Schengen Information System (SIS) that contains criminal suspects’ surveillance records will be accessible, albeit to date its worth has been hindered by information input restrictions and lethargy over participation.

Mr Trump’s recent mistakes in breaching one of the most basic terms of intelligence agreements – not sharing with third parties – will make many countries more wary of sharing its secrets with the US in the future. But while there is great reliance on America’s massive intelligence resources, it’s worth remembering too that it’s not all one-way traffic. The US also relies on partners all over the world to serve as its own proxy eyes and ears.

The bottom line is that right now, faced with the challenges of transnational terrorism and even with the inherent systemic problems of intelligence sharing, no country can really afford to go it alone. The Islamic State group and al-Qaeda are no slouches on the intelligence front. Global counterterrorism intelligence collaboration is more vital than ever.

As Bernard Squarcini, another French intelligence official once succinctly put it: “Either we get organised, or we get eaten up”.