Want to know a secret and promise not to tell?

One of Charlie's colleagues used to be fond of saying, "Just between you, me and the gatepost ..." as he passed on yet another secret that he should have been keeping.

Finally an exasperated Charlie said, "If it's a secret, then I don't want to know."

To which the colleague replied, "No, no, but I want to tell you."

In an ever shrinking modern electronic world, not only have the goalposts moved, but so has the gatepost. It seems it's harder and harder to keep a secret.

In building a $2 billion advertising business in Australia where many of our company's clients were competitors with each other, it was essential that we all had secrets and kept them. And from the very beginning, keeping a secret and developing trust were essential if we were all to survive and succeed. And so we did.

Business people at all levels know about trust and it's the same between countries. Prime minister John Howard had a strong bond of trust with George Bush. John Kennedy, after a very rocky start, established a trust with the president of Russia, Nikita Khrushchev, that got them through the Cuban missile crisis of October 1962. And the world breathed a sigh of relief. Kennedy went on to establish great trust with the American people that can still be seen in the depth of sadness that persists today as they mark the 50th anniversary of his assassination. Howard, as PM, developed a trust with the people he called "the battlers" - Australia's middle class. They trusted him with the economy and our relationships with our neighbours. And so he had 11 years of power.

But sometimes secrets can bring people undone. Many times when an executive has approached me to say, "We've got a problem here, what should we do?", I'd say, "Why don't we just tell the truth." Invariably, it would work.

President Nixon should have learnt the lesson. After all, Watergate was a basic bungled burglary. "Too much alliteration!" screams Louise. But, in fact, it wasn't just alliteration; it was Nixon trying to keep a secret.

There should be no secrets between trusted people, businesses or allies.

However, when you really need to keep a secret from your competitors, then take a tip from the best.

Coca-Cola's famously secret recipe was invented by Dr John Pemberton in 1886. It is still known only to a few employees. The formula was stored in a vault at the Trust Company Bank in Atlanta until 2011 when it was moved into a purpose-built chamber as part of the company's permanent interactive exhibition, the World of Coca-Cola, in Atlanta, Georgia.

And in another southern American state, Colonel Sanders mixed 11 herbs and spices together and rubbed them on a chook. That original recipe is kept in a vault in KFC's Louisville, Kentucky, headquarters. For added security, two companies, unknown to each other, produce half the recipe each.

But there's no information available about where Google keeps its secret algorithm that has powered its search engine and its consequent domination of the online world.

However, when it comes to national security, the most famous secret about breaking secrets was the British use of the Enigma deciphering machine that decoded German and other enemy communications during World War II.

And, of course, the Australian triumph in the world of great secrets is Vegemite. The original secret recipe is still being produced by Kraft Australia and the billionth jar was sold almost exactly five years ago.

There are a couple of secrets I would like to crack, muses Louise. "Where do lone socks go to and why do coat hangers multiply ... and is there a relationship between the two?"

Harold Mitchell is an executive director of Aegis.