ON JULY 8, Britain released a new Strategic Defence Review (SDR), the Labor government's first comprehensive assessment of British security requirements through 2015. Released as a "white paper" (a policy document), the review concluded that while there is "no direct military threat to the United Kingdom or Western Europe," the country's "minimum deterrent remains a necessary element of [its] security." But, the paper stated, "We have concluded that we can safely make further significant reductions from Cold War levels, both in the number of weapons and in our day-to-day operating posture."
Currently, the Royal Navy's fleet of three Vanguard-class (Trident) ballistic missile submarines (SSBNs) comprises the country's nuclear deterrent force. (In March, the Royal Air Force withdrew from service the last of its WE-177 nuclear gravity bombs.) According to the review, Britain will maintain four SSBNs, the same force envisioned by the previous government. The HMS Vanguard, HMS Victorious and HMS Vigilant are now in service; the fourth boat, HMS Vengeance, is expected to be commissioned around the year 2000. Britain expects that the Trident force will meet its nuclear deterrence requirements for the next 30 years.
The SDR concluded that Britain needs a nuclear stockpile of less than 200 operationally available warheads—some 100 fewer than the maximum level proposed by the previous Conservative government led by Prime Minister John Major. The new level represents more than a 70 percent reduction in the explosive power of Britain's operational force since the end of the Cold War. The SDR also determined that Britain does not need more than the 58 Trident II submarine-launched ballistic missiles (SLBMs) that have already been delivered or ordered (seven fewer than the Major government proposed). Finally, the review also announced that only one SSBN will be kept on patrol at any given time (the United States keeps between eight and 11 of its 18 SSBNs on patrol), and that it will be armed with 48 warheads rather than the 96 announced by the previous government.
During the Cold War, British SSBNs had the capability to fire nuclear weapons within minutes of receiving authorization. Under the new SDR, SLBMs will be "detargeted" and the submarines will be prepared to fire within a period of days. More advanced dealerting measures, such as taking submarines off at-sea patrol and removing warheads from their missiles, were examined during the SDR but rejected. "Ending continuous deterrent patrols would create new risks of crisis escalation if it proved necessary to sail a Trident submarine in a period of rising tension or crisis. The further step of removing warheads from missiles would also add a new vulnerability to our deterrent posture. This is a particular concern given our reduction to a single nuclear system," the report said.
In the SDR, Britain became the first nuclear-weapon state to disclose the total composition of its defense fissile material stocks, declaring a stockpile of 7.6 metric tons of plutonium, 21.9 metric tons of highly enriched uranium (HEU) and 15,000 metric tons of other forms of uranium. Although the United States has provided a more detailed breakdown of its plutonium stocks, it has not yet declared its stocks of HEU.