Nuclear deterrence has been a major pillar of British defence policy since the mid-1950s. The United Kingdom maintains a minimum, credible, independent strategic nuclear deterrent force, assigned to the defence of NATO. Its purpose is purely defensive: to deter the most extreme threats to the security of the UK and to that of her NATO allies.
Potential adversaries must thus take into account the UK’s nuclear capabilities when facing UK conventional forces deployed as part of NATO’s forward deterrence and defence posture, not least the UK-led battlegroup in Estonia. The UK does not see a contradiction between cooperation with allies and having an “independent” deterrent – its nuclear force is operationally independent and only the UK Prime Minister can authorise the use of the UK’s nuclear weapons, even as part of a wider NATO response.
Today, the Soviet Union is gone – yet a weaker but more dangerous Russia as well as an increasingly powerful China create a potential “two peer” nuclear challenge. The UK is currently renewing its nuclear deterrent as the existing capability is aging – but continues to seek opportunities for multilateral nuclear disarmament as the strategic circumstances allow. In light of the international security environment, the 2021 change to the warhead ceiling reflected that. But the UK needs to ask itself whether bigger changes will be needed for the future.
Download and read: British Nuclear Policy (PDF)