Amidst all the current sabre rattling on the Korean peninsula, one report has significantly upped the stakes – the apparent ‘leak’ of a confidential US intelligence report stating that the North Korean regime has a nuclear bomb that can be launched on a missile.

Previous reports have cast doubt on the regime’s ability to produce a bomb small enough to be carried on a missile. Now, it seems, there’s a secret US intelligence report that says it may well be able to do just this.

How has this report come to be ‘leaked’? The key paragraphs were read out by a supposedly little-known politician, Doug Lamborn, during a meeting of the House of Representatives Armed Services Committee.

You can take your choice of explanation. One is that it’s a genuine leak of a document inadvertently obtained by Mr Lamborn and released by mistake into the public domain. The second, more interesting one – at least from the point of view of how states choose to communicate  –  is that it’s not actually a leak at all but an attempt by the US Government to imply it believes the North Korean weapons programme is more advanced than it really is.

Why would it do that? Simply, to persuade North Korea’s Chinese allies that the bellicose warnings of war emanating from Pyongyang could actually be taken seriously. Iraq-watchers may well recall the dire ’45 minute’ claims made for Saddam Hussein’s arsenal, which were used to justify preparations for war.

In a high-stakes game of poker such as this, there is much to be gained by suggesting to the other side that while you believe they have a very strong hand, yours is stronger – and that you’re prepared to play it.