Thirty years ago this week, French secret agents destroyed the Rainbow Warrior. The Greenpeace flagship had been involved in high-profile protests over French nuclear testing in the South Pacific and agents from the French General Directorate for External Security (DGSE) were sent to prevent it leaving New Zealand for another protest campaign at Mururoa Atoll. Just before midnight on the evening of July 10, 1985, two explosions ripped through the hull of the Rainbow Warrior, killing a Portuguese crew member, Fernando Pereira, and sinking the vessel alongside Marsden Wharf in Auckland.

The French attack was directed against an international non-government organisation. New Zealand wasn’t the target, but most New Zealanders, and for that matter most Australians, did not make such a distinction. The fact that a terrorist act was committed on New Zealand territory by a supposed friendly nation triggered a deep sense of outrage and a serious deterioration in relations between New Zealand and France that took many years to repair.

Consequently it’s not without some irony that this week saw a major revelation of highly secret French intelligence activity carried out by the same organisation that bombed the Rainbow Warrior.

“The French would be particularly keen to gather intelligence on Australia’s key economic relationships and defence contracting.”

It’s a disclosure that has received virtually no media coverage in the English-speaking world, but it’s of direct significance to both Australia, and New Zealand, as well as many other countries: namely that France is tapping the major undersea fibre-optic telecommunications cables that link East Asia, South and South-East Asia and the Middle East, as well as Australasia and the South Pacific, to Europe. To put it plainly: France is intercepting the bulk of Australia’s internet and telecommunications traffic with Europe.

In an exclusive and well-sourced report in the wake of WikiLeaks’ recent disclosures of American intelligence targeting of successive French presidents, the French weekly magazine L’Obs (formerly Le Nouvel Observateur) has revealed that in early 2008 former French president Nicolas Sarkozy secretly gave the DGSE authorisation to intercept submarine telecommunication cable communications for an initial period of five years.

The massive project, agreed between Sarkozy, French prime minister François Fillon, and DGSE director Pierre Brochand, involved expenditure

of some €700 million (more than

$A1 billion) and the engagement of 600 staff to harvest data from the major fibre-optic links either making landfall in France or passing through French territorial waters.

According to L’Obs, at least five major cables have been tapped with the help of the French telecommunications companies Orange and Alcatel-Lucent: the TAT-14 cable to the United States; ACE to West Africa; the I-ME WE cable to India; and the SEA-ME-WE 3 and 4 cables to South-East Asia, East Asia and Australia.

Secret interception facilities were installed at the submarine cable landing facilities at Marseille on France’s Mediterranean coast, the landing point for the SEA-ME-WE-4, and at Penmarc’h in Brittany, the landing point for the SEA-ME-WE 3 cable.

President François Hollande has reportedly authorised the DGSE to extend these cable interception operations with a new five-year intelligence collection plan from 2014 to 2019. France’s newly passed electronic surveillance law provides the necessary legal framework.

According to information obtained by L’Obs, France’s national security interceptions control commission has approved the interception of cable traffic from 40 countries, including Algeria, Morocco, Tunisia, Iraq, Syria, Sub-Saharan Africa, Russia, China, India and the United States, as well as Australia and New Zealand.

France’s investment in submarine cable interception followed similar shifts in signals intelligence collection by the US National Security Agency (NSA) and its “Five Eyes” partners, including the Australian Signals Directorate (ASD), as high capacity fibre-optic cables became the backbone of global telecommunications infrastructure and the internet.

As most international telecommunications traffic now travels long-distance through fibre-optic cables, Australian National University intelligence expert Professor Des Ball says that intelligence collection from such cables has become “extremely important”.

Top-secret documents leaked by former US intelligence contractor Edward Snowden and other disclosures have shown that both the US and Britain have utilised their access to undersea fibre-optic cables to pursue a “collect it all” approach to internet traffic, heralding what one NSA document proclaimed as a “golden age” of signals intelligence.

A top secret NSA map, published by the Dutch newspaper NRC Handelsblad last year, shows that the US and its Five Eyes partners, Britain, Australia, Canada and New Zealand, tap high-speed fibre-optic cables at 20 locations worldwide. The interception operations involve co-operation with local governments and telecommunications companies, or else through “covert, clandestine” operations.

It has also been revealed that the Australian Signals Directorate has been in partnership with British, American and Singaporean intelligence agencies to tap the SEA-ME-WE-3 cable that runs from Japan, via Singapore, Djibouti, Suez and the Straits of Gibraltar, to northern Germany. Australian access to the intercepted data comes through close co-operation with the Singaporean Ministry of Defence, which taps the cable with co-operation from Sing Tel, the telecommunications company that manages the cable, which lands at Tuas on Singapore Island’s west coast.

Intelligence has been a key element in an expansion of Australian–Singaporean defence co-operation over the past 15 years. This week, Prime Minister Tony Abbott announced a further strengthening of intelligence and security ties with Singapore.

Australia is connected to the SEA-ME-WE-3 cable by a link from Singapore to Perth, where Australia’s intelligence agencies also directly harvest data. “Foreign communications” – defined as anything “sent or received outside Australia” – are collected in bulk under ministerial warrants issued under the provisions of Australia’s Telecommunications (Interception and Access) Act 1979. While Australian citizens and permanent residents are largely excluded from intelligence reporting derived from this data, documents disclosed by Snowden show that the ASD is happy to share data in bulk with Australia’s intelligence partners, including the NSA and Britain’s Government Communications Headquarters.

Melbourne University intelligence expert and research fellow at the Nautilus Institute for Security and Sustainability Richard Tanter said the latest French revelations were part of a broader picture, largely revealed by Snowden as well as disclosures by WikiLeaks, that showed the US, its Five Eyes partners and other allies and rivals, including France, had gained “a stranglehold on global communications with comprehensive access to internet traffic across every continent and every ocean”.

“The French would be particularly keen to gather intelligence on Australia’s key economic relationships and defence contracting,” Tanter said. “They would also be very interested in Australia’s attitude towards their colonial possessions in the South Pacific, especially in the lead-up to New Caledonia’s independence referendum, which is set to be held in 2018.”

However, the revelation of French access to Australia’s primary telecommunications links to Europe appears unlikely to adversely affect bilateral ties, which include a 2013 agreement to increase “strategic co-operation in the Pacific region … [and] co-operation on current and future defence materiel programs”.

France is one of the potential contenders for participation in Australia’s future submarine project and will presumably be keen to gather any intelligence it can on its prospects and Australia’s attitude towards other bids, such as from Japan, Germany or Sweden.

Thirty years on from the bombing of the Rainbow Warrior, the DGSE is still very much in business and it’s no surprise that French protests about American espionage have been muted. Electronic spying is ubiquitous and directed as much towards friends as it is against potential adversaries.