Dominic Lawson: Gossip is gold dust for diplomats

The cable went on to say that contacts' revealed this alleged 'hound-dog' to have manic-depressive tendencies

Hillary Clinton, we are told, has been spending the past couple of days ringing up various world leaders to apologise pre-emptively for any disobliging pen portraits of them emerging from the distribution by WikiLeaks of a quarter of a million confidential State Department cables.

As it turned out, this vast cache of diplomatic gossip has revealed nothing very scandalous. The German Chancellor, Angela Merkel, is described as "seldom creative"; President Sarkozy of France as "thin-skinned and authoritarian"; the Italian Prime Minister, Silvio Berlusconi, as "physically weak ... [his] frequent late nights and penchant for partying hard means he does not get sufficient rest". And so on and so – very unsurprisingly – forth.

Perhaps it is also unsurprising that so little of this much-anticipated cache is red hot. All the material comes from the US defence department network known as Siprnet, to which an estimated 2.5 million US military and civilian personnel have access. Indeed, the leak itself is thought to be the work of a mere private, an intelligence analyst who was arrested and charged last June for an earlier public dissemination of classified US documents.

Some of the material, however, will tantalise the media, not least in this country. One cable shows the US embassy in London passing on intelligence about a minister in the last Labour government, to the effect that the man "remains a bit of a hound dog where women are concerned". The cable went on to say that "contacts" revealed this alleged "hound-dog" to have "manic-depressive tendencies". The head of the office of intelligence operations cabled back to London saying how much they valued this "particularly insightful and timely" material about the minister's "possible depression and scandals, as well as comments on the state of his marriage ... we would greatly appreciate additional information".

Why would the recipients of this information be so pleased, and want more where that came from? Is it likely that the US State Department would have wanted to blackmail the minister in question, in order to further America's foreign policy objectives? No, that is altogether too novelistic a construction. What we have always to bear in mind is that secret intelligence is above all designed to supply the material that a particular government has asked for. The best analogy is the relationship between a newspaper editor and a newsdesk reporter, with the Prime Minister in the first role and the intelligence officer in the second. The career-conscious reporter will do his best to find out the material that he knows is the sort of thing his editor finds most fascinating, not what he personally finds most compelling.

Now, what prime ministers tend to find most fascinating are the foibles and weaknesses of their opposite numbers in other countries. This is not a matter of mere vicarious curiosity – although the human love of gossip can never be over-estimated. It is also the case that if you are negotiating personally with someone, and trying to pitch your negotiating tactics at exactly the right psychological level, it is not nearly enough to know what your counterpart wants: you want to understand how his mind works.

This, at least, is the explanation given to me by a former senior British intelligence officer, who said that "the politicians were always especially excited by any titbits of personal information we could come up with about their opposite numbers from other governments; so naturally we would do our best to oblige".

This is worth bearing in mind the next time you hear a politician reprimand a newspaper, or a television interviewer, for asking questions of a personal nature, and telling the allegedly importunate questioner that he or she "should stick to the issues". It may well be that the minister is right to imagine that the general audience wants to know more about "the issues" – but the idea that politics in the raw does not revolve around the interplay of personalities is hopelessly naive. The study of politics at the highest level is the study of human nature – and you don't need to have read the plays of William Shakespeare to realise that.

For example, suppose you were a European foreign intelligence officer working in Britain in the earlier years of the Blair/Brown duumvirate and that your government had assigned you the unenviable task of trying to anticipate whether or not Gordon Brown's "five economic tests" would lead to a recommendation that Britain joined the euro. You might very well have gone half-crazy trying to get your head around the facts and figures of macroeconomic convergence, and what the British Treasury was going to make of it – and still not come up with any real sense of the likely direction of policy.

However, suppose you had understood the single most relevant fact about the then Chancellor's personality – that he was so filled with resentment at the fact that Tony Blair was the Prime Minister that he would do anything to block 10 Downing Street's pet projects; combine that with the fact that Blair was known to be passionately enthusiastic about entering the euro (even while delegating the consultative process to the Treasury), and you could absolutely assure your bosses back in Bonn that the British Chancellor would veto the idea.

The validity and significance of this crude psychological point was given confirmatory chapter and verse in The New Machiavelli, the recent political memoir by Jonathan Powell, Blair's long-serving chief of staff. Powell reveals that "Following the 2001 election ... Gordon said that he would only agree to the euro if Tony stood down as leader." In other words, while Brown claimed to oppose euro membership on economic grounds, it was simply another issue that could be horse-traded in return for purely personal interests.

Of course, intelligence services are principally charged by their political masters to find out real facts about the strategic and military plans of hostile powers. Yet here too, psychology plays a much-underestimated role – the psychology of the information's recipient, that is. The history of espionage tells us how the best and most vital information is liable to be ignored if the leader that receives it does not want to believe what has been presented to him. Perhaps the most notorious example was Stalin's refusal in 1941 to credit the intelligence by the Soviet Union's most brilliant agent in the field, Richard Sorge, that the Nazis were about to invade. Sorge gave extraordinary details, accurate even down to the day that Operation Barbarossa was to start; but because Stalin could not face up to the idea that his non-aggression pact with Hitler was worthless, he furiously denounced Sorge's information as mere provocation.

Another example of this was the Israeli government's being caught cold by Egypt's military assault in October 1973: it had received substantial and detailed intelligence to the effect that such an attack was imminent (up to and including the battle positions of Egyptian army units) – but at some visceral level did not want to believe it.

This form of psychological failure to assess intelligence properly can work in precisely the opposite direction: in 2003 the US and British governments had been so convinced of Saddam Hussein's possession of "weapons of mass destruction" that there was no information (secret or otherwise) which could have persuaded them to the contrary – as Hans Blix, the head of the UN's weapons monitoring team in Iraq, discovered.

In the end, secret intelligence, like the politics it serves, is perpetually compromised by human frailty.

d.lawson@independent.co.uk