As an active intelligence alliance, the Five Eyes club is a partnership forged in wartime to monitor enemy radio transmissions, and now monitors billions of private communication worldwide.

So what exactly is the Five Eyes club and what is its role today? Let's take a look.

The Five Eyes is an alliance comprising Australia, Canada, New Zealand, the United Kingdom and the United States for joint cooperation in signals intelligence.

The origins of the club dates back to the Second World War. Britain and the US cooperated with radio transmitters to intercept enemy exchanges. This cooperation continued after the war, and the alliance expanded to five by 1956. 

As communications technology developed dramatically, their activities evolved. It expanded to human intelligence, counter-espionage, spatial intelligence and financial and transportation security cooperation. 

Professor Shen Yi from Fudan University has revealed in a recently published article that the Five Eyes have been exchanging classified information on China's foreign activities. 

He says the US is mainly responsible for the coordination of Chinese investment intelligence services, and Australia has committed to defending against China's political influence. 

Whistleblower Edward Snowden once described the alliance as a supranational intelligence organization that doesn't answer to the known laws of its own countries.