Five of world’s most powerful nations pledge to avoid nuclear war

US, Russia, China, the UK and France who are permanent members of the UN security council agree nuclear war cannot be won'

Five of the world's most powerful nations have agreed that a nuclear war cannot be won and must never be fought" in a rare joint pledge to reduce the risk of such a conflict ever starting.

The pledge was signed by the US, Russia, China, the UK and France, the five nuclear weapons states recognised by the 1968 Nuclear Non-Proliferation Treaty (NPT) who are also the five permanent members of the UN security council. They are known as the P5 or the N5.