Three navies other than the U.S. Navy currently operate and deploy nuclearpropelled ballistic-missile submarines (SSBNs)—Britain, France, and Russia.
The Royal Navy has four Vanguard-class SSBNs, completed between 1993 and 1999. The boats each carry 16 American-built Trident D-5 missiles with British warheads. Since July 1998 the lone SSBN normally on patrol carries 48 nuclear warheads, but it is probable that a balanced loadout of three warheads per missile is not carried on all missiles.
These are Britain's only operational nuclear weapons; the last WE177 bombs, carried by Royal Air Force and Royal Navy aircraft, were retired in 1998. Thus, the British SSBNs are now additionally assigned a "sub-strategic" nuclear strike role, but without changes in their armament except for the warhead loadout.
The French Navy also has four SSBNs-three of the new Le Triomphant-class (completed in 1997-2004) and one of the Le Redoubtable-class, (1985). The latter will be replaced about 2010 by the fourth Le Triomphant SSBN, being built at the naval shipyard in Cherbourg.