US President Joe Biden has vowed to defend “every inch” of NATO territory this week as Russia and Ukraine continue to fight. Speaking at the NATO summit in Madrid, he said that the alliance would be “prepared for threats in all directions”, a reference to the aggression of Russian President Vladimir Putin. NATO allies have helped Ukraine with arms supplies during the conflict, and experts believe that the war has now brought Western nations and Russia closer to direct fighting than they have been for decades. Former NATO Deputy Secretary-General Jamie Shea was asked by Times Radio this week about the Western world and Russia is “closer” to a “hot war” than they have been in a long time.

He replied, “Yes, [but] Of course, this does not mean that a war between Russia and NATO is inevitable.

“Putin has his hands full with Ukraine at the moment, which does not indicate that he has either the means or the intention to attack a NATO member state.

“But NATO policy has always relied on deterrents. The ability to quickly gather enough force to show that it can defend its territory and therefore deter aggression.

“NATO believes that, due to the perceived threat from Russia, it needs more troops [and is] goes from 40,000 soldiers on high alert to 300,000 soldiers.

“What was unthinkable 10 years ago is unfortunately now in the realm of the conceivable.”

Finland and Sweden were formally invited to join NATO this week after decades of neutrality.

The two Nordic nations have expressed concern about the invasion and possible spillover effects, both sharing borders with Russia.

But Putin has warned that he will “respond in kind” if NATO infrastructure and troops are deployed in Sweden and Finland.

On Wednesday, he said: “There is nothing that can worry us about Finland and Sweden becoming NATO members. If they want to, please, go ahead.

“But they should clearly understand that they did not face any threats before this.

“Now, if NATO’s infrastructure and troops are deployed, we will have to respond in kind and create the same threats to the territories where the threats against us are created.

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General Sanders added: “During all my years in uniform, I have not felt such a clear threat to the principles of sovereignty and democracy and the freedom to live without fear of violence as President Putin’s brutal aggression and his expansionist ambitions.”

Anti-UK rhetoric has continued to run in Russian media this week.

A retired Russian general and military expert warned that Britain would “physically cease to exist” if the new conflict in Lithuania triggered a third world war with nuclear power.

He also targeted General Sanders for his comments.

Lieutenant General Evgeny Buzhinsky said: “He does not understand that Britain, as a result of the Third World War, will physically cease to exist.

“The island will disappear, so I have no idea where he or his descendants will live.”