Cost of Russian victory in Ukraine too high: Johnson

STORY: Speaking at the start of a Group of Seven summit on Sunday, Johnson said the West needed to maintain its unity in the face of Moscow's aggression.

He added that leaders have to have an honest discussion about the pressures countries are facing.

"But the price of backing down, the price of allowing (Russian President Vladimir) Putin to succeed, to hack off huge parts of Ukraine, to continue with his programme of conquest, that price will be far, far higher. Everybody here understands that," he said.

G7 leaders are expected to show a united front on supporting Ukraine for as long as necessary and cranking up pressure on the Kremlin, though they will want to avoid sanctions that could stoke inflation and exacerbate the cost-of-living crisis affecting their own people.