Intelligence, intelligence. There must be four or five inquiries underway.

The president has ordered a special commission, Mr Blair wants an inquiry, all to know if the intelligence that justified the March invasion was well-meant, accurate, faked or all wrong.

Until, I'd say, the Second World War, the dictionary definition would cover most people's understanding: "intellect, understanding, sagacity".

There is in my dictionary a final sub-definition of intelligence and it meets our case: "the gathering of information secretly, usually on behalf of some government agency".

Ahah - a very ancient word revived. I recall, in Shakespeare "intelligence, sirs".

Look that up and you get the short English definition of the CIA and the FBI: "a secret agent, a spy".

Secret agent is not quite right for the FBI men who regularly announce themselves as agents in an investigation, but exactly right about the CIA - Central Intelligence Agency.

Nobody goes around in the CIA with an identification card and indeed they're almost always known to society, even to the wife, as a businessman, an insurance agent, some respectable profession actually worked at or assumed as a cover.

The CIA was not invented until 1947. It was a vague sort of service and was infested, in Washington especially, by amateur cloak-and-dagger people and gossipy socialites who could barely wait to hint that they were working quietly for - well, you know who.

In 1947 one Allan Dulles, the brother of a coming secretary of state, organised a really professional spy organisation - the Central Intelligence Agency - to co-ordinate foreign intelligence dangerous to United States' security.

The public knew who was the appointed head of it but that was about the end of public knowledge.

I don't know how it is with the equivalent outfits in European countries, but the CIA to most folks has always carried a sinister air about it - inevitably when you reflect that the only time it comes into the news is when some project, some operation, like the Bay of Pigs invasion, has gone sour or a CIA man has been caught as a Russian agent.

This sinister reputation is popularly redeemed mainly by the nick-of-time rescue of James Bond. And 007 is saved again for yet another lethal encounter with Charles Gray and his pussy cat.

The FBI, on the other hand, has maintained a worthy reputation from the beginning.

Perhaps I shouldn't say from the beginning because in 1908, when it was formed, it was probably unknown to the average citizen.

It was organised as the investigating arm of the Department of Justice with practically no police powers.

I ought to say at once that the United States, unlike many countries, has no national police force - that rests entirely with each state which, remember, has its own education system, banking laws, each has its own criminal code.

In the making of the Constitution in the late 18th Century James Madison succeeded in convincing the founding fathers that the best way to prevent a dictator or the national government taking over the country was to give the states great governmental powers.

Not until the 1920s did a famous attorney general persuade Congress to give the FBI powers of investigation that would in time make it a clearing house and central consulting agency for crime all over the country.

The provocation for giving the FBI unprecedented authority was the crime wave that flowed alongside the oceans of illegal liquor and the bootleggers that bought and sold them.

There was a time in the mid-20s when, as an example, the notorious Al Capone practically owned the government of Chicago.

After every murder of a rival gangster he would stage an elaborate funeral procession for his "friend" and appear at it without shame or fear since he'd already paid off witnesses, law makers, police, prosecutors, even judges at the coming trial.

When Roosevelt repealed prohibition and the big gangsters turned to other rackets many of their hacks turned to bank robberies, and that's when the FBI was given for the first time the right to investigate any crime that involved crossing a state line.

It had been the custom for two or three men to rob a bank and then quickly drive across the state border and have a relaxed supper at a hideaway in a state near or far.

But now the FBI, once let loose, for the first time armed and licensed to kill, went off on a national chase.

They became national heroes, known as the G-Men, the gang busters, and in no time spawned radio serials and made the gangster film as classic a film as the Western.

The headquarters of the FBI in Washington expanded into an unmatched exhibition hall and forensic laboratory of crime.

Until very recently it was one of Washington's compulsory tourist attractions, showing innumerable methods of detection, inviting visitors to add their own fingerprints to the original stock of six million, and take a tour of the forensic laboratory to goggle at physicists and biologists and chemists scraping soil from boots, threads of hair, bits of grass, and spectro-chemists examining life-threatening letters to the president. The usual catch is over a thousand a month.

Today the FBI have become the first government agency to recruit agents for any crime that might have been plotted in, or initiated in anyway outside the state it was committed in. For over 20 years it's had a working anti-terrorist squad.

I think few people remarked on the speed with which the bureau came to identify and learn the life stories of 16 of the 19 suicides who shattered the Twin Towers and the Pentagon.

There was a time when the FBI acquired an unpleasant, predatory reputation, during Senator McCarthy's manhunt for Communists in the government.

That ended when McCarthy went too far in humiliating the army by implying that it was riddled with Communists.

The Senate censured him - a very rare punishment - and he relapsed into his alcoholism and died.

My own contacts with the FBI have been few and far between. In the late summer of 1968 a young man who looked like Jimmy Stewart knocked on the door of the Long Island retreat and wanted me to recite my version of the scene in the Los Angeles hotel pantry where I'd seen Bobby Kennedy assassinated.

I had one, I suppose you'd call it, "encounter" - the right word, one that I cherished as a delightful encounter.

In 1943 when America was well in war I went off on a one-man tour of the country to report on what the war had done to every sort of trade and specialty, from concentrating orange juice for British children, making parachutes out of long-staple cotton in Arizona, to the secrecy of the Navy's sudden marine net in San Francisco to tattooing parlours in San Diego.

For this tour, need I say, I had to be provided with a pack of credentials, a State Department, Department of Agriculture ... on and on - including an FBI clearance for many wartime agencies, especially the army, navy, marines, so on.

It was spring and I was on a day-long train ride across Texas on my way to look at an airforce base at the western edge of the state.

I found myself seated next to a buxom, middle-aged matron, well dressed.

After a little small talk I told her what I was up to and opened up a map and pointed to assignments just done with - Fort Riley, Kansas - the last cavalry base, now down to Miami to watch the airforce take over the big Miami hotels and now coming west to an airforce base.

She listened to all this with a deeply understanding smile, as if she'd just been introduced to some obscure mathematical problem.

I told her the name of the tiny town where I was getting off, one of those western names like Low Hills or Odessa.

We had lunch together and afterwards the lady went off for a long stretch, I assumed to the bathroom.

I later discovered I was wrong - she'd gone to the conductor to urge him to use whatever means he had to get in touch with the police, the FBI maybe, in Low Hills.

Well eventually we slowed down and stopped at Low Hills - there was no station, just a telegraph shack and the town name.

I got off and there to stop my exit and greet me, as arranged, was the base commander - a colonel, his aide - a major, and the FBI man.

We stood and waited for the chauffeur and the train swiftly pulled away.

And there on the train's observation platform, a tiny figure now, but still the smiling buxom matron.

And the train slid into the horizon bearing one proud American who had just performed a patriotic act: she had spotted and turned in a spy!


Letter from America audio recordings of broadcasts ©BBC. Letter from America scripts © Cooke Americas, RLLP. All rights reserved.