This is the moment a French warship withstood a mine blast. France put her maritime fleet through its paces in preparation for what senior commanders said are "increasing threats" from Russia.

The 150 crew members of the La Fayette-class frigate Courbet were shaken when the mine was detonated at close proximity during an exercise to test the vessel's resilience in actual wartime conditions. The so-called shock test is part of France's innovative Polaris (Préparation Opérationnelle en Lutte Aéromaritime, Résilience, Innovation et Supériorité ) initiative, a series of high-intensity exercises originally launched by former Chief of the Naval Staff Admiral Pierre Vandier in 2021. With the Russian threat becoming ever more apparent, Polaris radically changed Nato's war gaming experience by introducing real and unannounced challenges, which maritime fleets are forced to counter and survive.

In December last year, the French Navy fired an F21 heavy torpedo from a nuclear-powered attack submarine (SSN) at the hull of the former OPV 'Premier-Maître L'Her'.

While it was the missile which was being tested then, the latest shock test against the Courbet, which took place off the coast of Toulon on January 25, was aimed at measuring the resistance of the frigate's defensive armour after it was updated in 2020, and how well its crew coped.

The last time France carried out such a test was shortly after the collapse of the Soviet Union, in 1995, when a 250kg TNT charge was positioned 40 metres deep and 30 metres from the frigate La Fayette.

The Royal Navy carries out similar stress tests, though arguably these are not being conducted in as a systemic way as the French Navy.

"In coming up with Polaris, Admiral Vandier completely rehauled the French Navy's wartime mentality," said maritime expert Prof Alessio Patalano of Kings College, London.

"He was absolutely clear that he wanted every single ship getting out of port to be ready to do anything from maritime security and humanitarian assistance to overcoming the enemy in combat."

Polaris includes several elements, ranging from introducing unscripted tactical scenarios to preparing crews for wartime scenarios, and was first properly tested in an exercise with the Italian Navy last year.

"This type of exercise is different because it isn't just a matter of manoeuvring vessels to a scripted game plan," he said

"They aren't choreographed. Everybody has to play to their best. You'll have a side which actually wins and one which loses, and neither knows what the other will do.

"Any professional navy has the safety of its people at the forefront, but ensuring that means ensuring they can carry out their mission in the safest possible way, and that means testing them before they ever get into battle. It means you have to push the envelope a little bit to get as close as possible to the realities of warfare. "

Prof Patalano added: "Nato's operation tempo has been increasing because of the growing threat from Russia. Admiral Vandier came up with Polaris before President Donald Trump's latest warnings that the Europeans should get their act together.

"This is a genuine attempt to achieve greater critical mass and therefore greater capacity to gain real exposure to the scenarios that Nato may be facing."