Gen Sir Roly Walker says west faces ‘axis of upheaval’ with increasing threats from Russia, China and Iran

Britain must be prepared to fight a war in three years’ time and double the lethality of its army as the separate threats of Russia, China, Iran and North Korea come to a head, the new chief of the army has warned.

Gen Sir Roly Walker, the chief of the general staff, told reporters that the west faced “an axis of upheaval” with increasing military ambition and that a conflict involving one of the countries could lead to “a significant detonation” in another theatre.