Biarritz, France | Leaders of the world's major democracies are sitting down to two days of G7 summitry in the south of France, hoping to restore the fraying unity of the West and get to the finish line on Monday evening (Tuesday AEST) without any fireworks from an irascible US President Donald Trump.

Mr Trump tweeted ebulliently on Sunday that the "leaders are getting on very well", but European Council President Donald Tusk earlier articulated the high stakes, describing the Biarritz gathering as a last-chance saloon for Western commonality of purpose.