Australia accidentally revealed the private information of the world's most powerful people, when it sent details from leaders who attended November's Brisbane G20 summit to the organizers of a soccer tournament. Once aware of the security breach, Australian authorities decided not to tell figures like Vladimir Putin and Barack Obama that their information had been shared.

In an email released under a freedom of information after a request by the Guardian, Australian immigration officials admit that the passport numbers, dates of birth, and visa details of 31 world leaders were accidentally forwarded to a local organizing committee of the 2015 Asian Cup soccer tournament.

"The cause of the breach was human error," an immigration officer wrote in the email. "[Redacted name] failed to check that the autofill function in Microsoft Outlook had entered the correct person's details into the email 'To' field. This led to the email being sent to the wrong person."

"Given that the risks of the breach are considered very low and the actions that have been taken to limit the further distribution of the email, I do not consider it necessary to notify the clients of the breach," it concludes.

The accidental disclosure of the information happened on November 7, 2014, eight days before the Brisbane summit on November 15-16. Among those who had their immigration details leaked were US President Obama, Russian President Putin, British Prime Minister David Cameron, German Chancellor Angela Merkel, Chinese President Xi Jinping, and Indian Prime Minister Narendra Modi.

The Brisbane G20 was the scene of diplomatic discord between the world's most influential countries. Russia deployed warships off Australian shores for the duration of the summit after Australian Prime Minister Tony Abbott threatened to "shirtfront" Putin, using an Australian sporting term that means to charge an opponent in the chest. Putin ended up leaving the summit a day early.

Australia also faced tension with Obama, who made a significant public speech on climate change and the environment despite Australian government attempts to keep those issues off the G20 agenda.

"Whatever Barack Obama did on the weekend was going to be a distraction. That's the reality," Assistant Minister for Infrastructure and Regional Development Jamie Briggs said in a public display of the anger within the government at the time. "He's a massive, a massive distraction wherever he is."

The Asian Cup organizing committee that received the private information told the immigration department that none of the confidential data had been passed on or stored.

Australia's staging of that event in January proved more successful, and the hosts won the tournament after beating South Korea 2-1 in the final after extra time.

Follow Scott Mitchell on Twitter: @s_mitchell