Following through on its April 1995 commitment, Britain's Royal Air Force withdrew from service the last of its estimated 100 WE-177 tactical nuclear bombs on March 31. The WE-177s, some of which were located in Germany, are likely to be dismantled. The withdrawal of the WE-177s leaves the United States as the only country to have tactical nuclear weapons deployed outside of its territory (with several hundred weapons still in Europe).Britain now intends to rely on its fleet of Vanguard-class ballistic missile submarines for nuclear deterrence. The first three submarines in the class—HMS Vanguard, HMS Victorious and HMS Vigilant—have already entered into service. The fourth and final boat, HMS Vengeance, is scheduled to be deployed in the early 2000s, allowing Britain to keep two boats on patrol at any given time. Each submarine is equipped with 16 Trident II submarine-launched ballistic missiles capable of carrying up to eight warheads each. Britain, however, is not expected to keep its submarines fully loaded and, according to estimates by the Natural Resources Defense Council, its future nuclear stockpile may consist of a total of about 275 warheads.