Putin flirts again with grim prospect of nuclear war – this time he might mean it

Russian leader's speech marks biggest escalation of Ukraine war since it began, and raises fears around the world of unprecedented nuclear disaster

• Russia-Ukraine war: latest updates

This is not a bluff."

The message from Vladimir Putin's ominous morning speech, which marked the biggest escalation of the Ukraine war since the invasion on 24 February, was clear: Russia is willing to use nuclear weapons if Ukraine continues its offensive operations.