Tallinn: Australia will join the world’s biggest “live fire” cyber-war exercise, a week after Australia, the US and UK issued an extraordinary warning that Russian state-sponsored hackers were targeting key public and private infrastructure in Western countries.

The annual exercise, known as Locked Shields, takes place this week in Tallinn, Estonia, and tests the ability of government teams from countries across the world to withstand a full-scale cyber attack.

Last year the hostile state in the Locked Shields exercise was dubbed ‘Crimsonia’ – literally a red menace.

This year’s Locked Shields will simulate a hostile co-ordinated cyber-attack against a major civilian internet service provider and military airbase. The US and UK believe Russia has been working to develop the capability to launch such a strike since at least 2015.

Last year the hostile state in the Locked Shields exercise was dubbed ‘Crimsonia’ – literally a red menace – though organisers said it would not be “politically correct” to say it was modelled on Russia, and other countries could have the same capability and intent.