World gone MAD

Julian Lewis and John Woodcock make an important concession in their column about Britain’s nuclear deterrent: that its primary purpose is “to minimise the risk of being attacked by mass-destruction weapons in the hands of an enemy” (“Security by stalemate,” May).

To “minimise” is not to “eradicate,” and deterrence relies on all leaders being rational actors, who calculate to avoid mutually-assured destruction. Yet as the war in Ukraine underscores, we cannot rely on Putin—supposedly becoming increasingly unstable and erratic—to step back from the brink. The nuclear escalation we are currently witnessing leads all parties ever closer to accidental nuclear war—a miscalculation of incalculable proportions.

Keeping our nuclear weapons sends a signal to the rest of the world that security is dependent on them, and thus drives further proliferation. What moral authority can we have to lecture other states, such as Iran, to abandon their nuclear plans if we ramp up our own? Eighty-six countries around the world have now signed the Treaty on the Prohibition of Nuclear Weapons, and it is a mark of shame that the UK is not among them.

Caroline Lucas, Green MP for Brighton Pavilion