Conspiracy theories sprout like ivy and savagely grow to obfuscate the truth.

One such theory – eventually debunked with the release of a key file from the Public Record Office in Kew, the UK – claimed that British Prime Minister Winston Churchill and US President Franklin Rossevelt knew in advance about the Japanese attack on Pearl Harbour. According to the conspiracy, the Japanese were allowed to attack so that the US could be dragged into World War II.

The wreckage of the destroyers USS Downes and USS Cassin at Pearl Harbour drydock.

Unlike the fastidious scrambling of conspiracy theories, which admittedly creates high drama, the truth is often clear, even dull.

At 7.15am on Sunday, December 7, 1941, Japan launched a sneak attack on the US Pacific Fleet at Pearl Harbour, shattering the peace of a beautiful Hawaiian morning and leaving much of the fleet broken and burning.

The destruction and death that the Japanese military caused in Pearl Harbour that day – 18 naval vessels, including eight battleships, sunk or heavily damaged, about 300 planes destroyed, over 2,000 servicemen killed – was exacerbated by the fact that American commanders in Hawaii were caught by surprise.

The Japanese lost 27 planes and five midget submarines which attempted to penetrate the inner harbour and launch torpedoes.

The attack was described by President Roosevelt as “a date that will live in infamy”. That day drew America into World War II and changed the course of history.

Now, as the 75th anniversary of Japan’s devastating bombardment of the US Pacific Fleet at Pearl Harbour approached, Japanese Prime Minister Shinzo Abe became the first world leader to meet President-elect Donald Trump, seeking reassurances over the future of the US-Japan security and trade relations.

The explosion of the USS Shaw’s forward magazine during the Japanese attack on Pearl Harbour on December 7, 1941. The Shaw was repaired and served in the Pacific through World War II. Photos: Everett Historical/Shutterstock.com

Prime Minister Abe met the US President-elect in New York, where he is working to set up an administration after his surprise election victory last month that has injected new uncertainty into old US alliances.

The President-elect has said he would demand that allies such as Japan and South Korea contribute more to the cost of basing US troops in their countries.

Such comments have worried Japan at a time when the threat from North Korea is rising and China is challenging the US-led security status quo in the Pacific.

The savage attack, when no formal declaration of war was yet announced, was a great Japanese military blunder

“With the US, as elsewhere, being very much ‘a far away thing’ in most people’s minds, I have this suspicion that, at those times, the people in Europe, as those elsewhere, didn’t bother too much about the then existing Japan-US conflict,” John Consiglio, lecturer at the Faculty of Economics, Management and Accountancy at the University of Malta, said. “So, most probably, for quite a number of people, what they know about Pearl Harbour is what was mostly shown in that great film of the same name.”

He was referring to the 2001 blockbuster directed by Michael Bay and starring Ben Affleck, Kate Beckinsale and Josh Hartnett.

The Japanese attack on Pearl Harbour, as seen from the view of the Japanese.

Consiglio added that in such a context, it was even harder to really drum up a position about whether Washington, or President Roosevelt, really knew as much as is claimed about the then impending attack from the Japanese kamikaze.

“The film, again, has a specific scene in which one Japanese leader highlights the Japs’ total intention of relying 100 per cent on this element of surprise. And God knows how well that worked out for the Japanese,” he said.

There have been countless other historic events where, after their occurrence, big public debate ensued as to the extent to which national leaders would have had prior knowledge.

“In the case of Iraq, Ukraine, Ireland, Turkey and many of the current attacks by inland-based terrorists, after the event many, including journalists and those airport book writers, will often, or always, come out saying that this or that other leader knew about what was about to happen,” Consiglio explained, adding that despite what such scribblers will say and write, how could citizens really ever come to know the truth.

A Japanese photograph taken during the attack on Pearl Harbour. In the distance, smoke rises from Hickam Field.

“In many decision-makers’ minds there is always this type of approach of making sure that nobody knows what they might know in advance, in the interests of national security,” Consiglio said. “Therefore, citizens have been, are, and will always remain ignorant of what is about to hit us. I don’t think there’s much that the common man can ever do about this situation.”

For historian Lino Bugeja, the savage attack of the Japanese on Pearl Harbour, when no formal declaration of war was yet announced, was a great Japanese military blunder as that fateful day, ironically enough, sounded the death knell of the Japanese Empire.

“It happened at a time when the German panzers were wreaking havoc in Europe, when France had fallen and Erwin Rommel’s forces were unstoppable in North Africa,” Bugeja said.

“The Pearl Harbour attack compelled the US to join forces with the Allies and that was surely the major turning point.”