The memorial at the battleship Arizona which was sunk in the Japanese raid on Pearl Harbour

The memorial at the battleship Arizona, sunk during the Japanese raid on Pearl Harbour, 7 December, 1941


By Peter Rigby and Jacqueline Lang

On this, the 75th anniversary of the Japanese attack on Pearl Harbour, many of us are reflecting on the war in the Pacific. To this day, few people are aware that a small group of brilliant Australian code breakers played a vital, secret role in helping win the war by deciphering messages about where the Japanese were planning to attack.

Back in the early 1940s while the Pacific war raged, Sydney woman Hazel Treweek’s husband Athenasius whispered to her, “I can’t tell you anything about it, but Japan has just lost the war!”

Athanasius, a brilliant mathematician, had, along with other gifted intelligence boffins assembled at a secret location in Melbourne, just de-coded some vital Japanese military messages.

This Australian team was our answer to  Britain’s Bletchley Park group, which cracked the famous Enigma Code – and, though never adequately recognized  or celebrated, equally as important.


The top secret Australian codebreakers changed history at the Monterey Apartments in Melbourne

The top secret Australian codebreakers changed the course of history at the Monterey Apartments in Melbourne


The result of their efforts was that Allied forces had foreknowledge of, and were able to counter, most Japanese campaigns and battle plans throughout the Second World War.

Over the years since the war, the accepted belief has been that the US and Britain were responsible for the code breaking in the Pacific, whereas this group of extraordinary Australians were at the heart of it – and have never been publicly lauded for their brilliant work.

The Pacific War would have been far bloodier and more costly without these men, whose work remains an official secret to this day.

Could the Australian code breakers have been responsible for warning the US on 2 December 1941 that an attack in the Pacific was imminent? This claim has been made by some but the Australian government has never confirmed this.

Some historians maintain that the US was warned in advance. Yet when Japanese aircraft attacked Pearl Harbour that fateful Sunday morning five days later, the US military on the island seemed to be taken completely by surprise. In total, 2,403 Americans died and 1,178 were wounded. Eighteen ships were sunk or damaged, including five battleships. Hundreds of aircraft were destroyed, most of them never leaving the ground.


Pearl Harbour the day of the Japanese attack

Pearl Harbour the day of the Japanese attack


In the 70 years since the war ended, there has been much speculation about who knew what, and when, about the Pearl Harbour raid.

Fighting a losing battle against the Germans, then British PM Winston Churchill had been desperately trying to convince US President Franklin Delano Roosevelt (FDR) to enter the war in Europe to stop Hitler.

In early 1941, Roosevelt finally decided that the US would “win the war together” with Britain and told Churchill just that.


FDR and Winston Churchill

FDR and Winston Churchill


Meanwhile, information about Japanese military plans was cracking through the codebreakers’ wires in Melbourne and they were feeding this to the US, British and Australian Governments.

The timeline of events is interesting.

November 25, 1941: FDR received a “positive war warning” from Churchill that the Japanese would strike against America at the end of the first week in December.

November 26, 1941: Washington ordered both US aircraft carriers, the Enterprise and the Lexington, out of Pearl Harbour “as soon as possible”. This order removed 50 carrier-based planes; 40% of its already inadequate fighter protection.

November 29, 1941: US Secretary of State Cordell Hull told United Press reporter Joe Leib that Pearl Harbor would be attacked on 7 December.

December 5th, 1941, FDR wrote to then Australian Prime Minister John Curtin saying, “There is always the Japanese to consider. Perhaps the next four or five days will decide matters.”

December 7th, 1941: Pearl Harbour was attacked.

December 8, 1941,: The New York Times reported “Attack Was Expected” and that the US knew of the attack a week earlier.

The circumstances surrounding the Japanese attack on Pearl Harbour, and how much of a surprise it really was, are hotly debated to this day.


Australian troops at Milne Bay inflicted the first defeat on Japan - due to a tip-off from the codebreakers in Melbourne

Australian troops at Milne Bay inflicted the first defeat on Japan of the war – helped by a tip-off from the codebreakers in Melbourne


After Pearl Harbour, our Australian codebreakers went on to warn the Allies of some of the most important Japanese actions in the Pacific theatre, including the Battle of Midway and Japanese invasion of Milne Bay, both of which resulted in allied victories and turned the tide of war.

So Hazel was right: her beloved Ath was one of those responsible for helping the Allies win the war. For years, she quietly campaigned to have her husband recognised for being the true war hero that he was.

But sadly, to this day, much about the work of  Australia’s code breakers remains a secret.

Shortly before she died in 2005, Jacqui met with Hazel in Sydney and she opened up about her fascinating husband and their life together. Here’s what she had to say:


Hazel Treweek

Hazel Treweek


“My husband, Ath, was a genius, an unsung hero whose crucial work as a codebreaker helped change the direction of the entire war.

In the early 1940s, he was asked to work with a secret team of Australians and Americans, helping decipher Japanese naval messages.

Sadly, during his lifetime, nobody ever publicly recognised his vital contribution, as his work was top secret and remains classified to this day.

From the moment I met Athanasius Treweek in Sydney in1938, I knew he was a brilliant man. He was 27, an outstanding classics scholar who lectured in Latin and Greek at Sydney University. He’d also studied Japanese well before the war because he could tell trouble was looming.

I was attracted to him because he had a lively sense of humour from the outset. Our first date was to the ballet. Four years later we were married.


Major Ath Treweek during the war

Major “Ath” Treweek during the war


Ath then became an army officer and was transferred to Melbourne, operating out of a group of buildings in St Kilda called Monterey. That was where American military and a key group of Australians worked to crack the Japanese codes.

The unit gave advance warning of the Japanese plan to send troops over the Kokoda Trail to Port Moresby but sadly General Douglas MacArthur’s intelligence chief ignored the warnings.

Of course, Ath and I were never able to discuss his work; he’d taken an oath of secrecy. We lived in a small flat in Melbourne and survived on a modest wage, paying about two guineas a week rent.

In the morning I’d go to work as a teacher at a boy’s school and Ath would catch the tram to St Kilda.

At night, he’d get home about 6.30pm and I’d say “how was your day dear?” over dinner but we never discussed his work.

But one day – I’ll never forget it – he came home with a huge smile and said, “Japan has just lost the war! I can’t tell you anything but the Japs have just lost the war.”

Soon after that, came the news of the Battle of Midway (in the central Pacific in June 1942) in which four Japanese aircraft carriers were destroyed. So I put two and two together.


The furious battle at Midway stopped the Japanese advance in the Pacific

The furious battle at Midway stopped the Japanese advance in the Pacific and was a turning point in the war


I am convinced Ath cracked the code that led the Americans to know where the Japanese ships planned their next attack. Which, of course, ended the Japanese advance in the Pacific Ocean.

After the War Ath and I returned to Sydney where he worked as an academic and I continued to teach.

As the decades went by, Ath and I still never discussed his work as a codebreaker. But I think back to what happened soon after Midway. Most of the codebreakers were transferred up to Queensland but then General Douglas MacArthur stepped in, insisting that Ath stay put saying ‘Major Treweek’s transfer would be deleterious to the war effort.’

Often, late at night, some American military guy would come and bang on the door at around 2am and Ath would just get up and leave – back to work in St Kilda.

The work was enormously stressful, and he had so much broken sleep; it ruined his health. He developed an ulcer after the War.

I know it was frustrating for Ath when he and his colleagues uncovered information, which they passed on the authorities and was never acted on.

Ath did once say, ‘One of the dreadful things about intelligence is you can tell people what’s happening and they won’t believe you.’

I believe the Australians and Americans had advance warning on things that were not acted upon.


Hazel in 1948

Hazel in 1948


Despite all his brilliant work, Ath never even got a promotion. There was never anyone to push his barrow for him, because his work was so hush-hush.

But one day I asked a senior naval man if he’d put a word in for my husband, and it paid off. Ath got promoted to being a Lieutenant-General, which meant a bigger salary.

Years later, I also wrote to Prime Minister Gough Whitlam, pointing out that my husband’s name was not on the War Memorial in Canberra. He heeded me, because Ath’s name is there now.

Having recently had a heart operation, I’m not able to travel there to see it but I plan to get a photograph taken.

My wonderful husband died in 1995. Until the end, he retained his great intellect. Thankfully my passion for theatre, English, and Shakespeare has meant my years without him have remained rich and fulfilling.

I have worked as a teacher since the 40s, stopping for only a year or two when my children were very young.

For nearly 50 years I have worked from home, tutoring thousands of students from all walks of life. I directed my first play at 65 and I help judge the Shakespeare Award at the National Institute of Dramatic Art each year.

There’s a lot to live for, even without my marvellous husband. I can only walk with a walking frame, but the spirit is unbound.”

We hope that if you choose to share this article, Ath Treweek and his brilliant fellow Australian code breakers may become better known and remembered by our nation.





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