How Putin could humiliate NATO and send 600,000 troops to attack alliance's northern flank in lightning offensive

Ian Bond, deputy director of the Centre for European Reform, told the BBC that even if a full ceasefire is agreed in Ukraine, it is unlikely Putin's aggression would be abated.

'Nobody in their right mind wants to think that a European war is around the corner again. But the reality is an increasing number of European intelligence officials have been telling us that,' he said.

'Whether this is coming in three years or five years or ten years, what they are saying is the idea that peace in Europe is going to last forever is now a thing of the past.'