UGM-133 Trident D5
UGM-133 Trident D5 submarine-launched ballistic missiles (SLBM) arm the Ohio-class submarine component of the U.S. nuclear triad, and are the only U.K. strategic nuclear weapons, aboard the Vanguard-class. British versions use a U.K.-developed warhead, but the missiles are the same for both countries.
They are far longer-ranged and accurate than any preceding SLBM. Given they can fire from any waters, and have a maximum range of approximately 12000 km/7000 miles, they can hit intercontinental targets from their piers -- not a plausible operational scenario, but placing them on a par with land-based intercontinental ballistic missiles.
While the exact circular error probability of the U.S. version is classified, it is generally estimated to be in the 50 meter range. It is the only remaining U.S. nuclear missile with multiple independently targeted reentry vehicles banned from land-based intercontinental ballistic missiles. Its ability to deliver up to 12 W88 nuclear weapons per missile, each with a yield up to 475 kilotons, makes each Ohio-class submarine, with 24 missile launchers, an incredibly potent threat.
Missile range will vary with the number and weight of warheads carried, as well as decoys and other penetration aids.
As part of a larger program of Precision Global Strike, to give a rapid-response, non-nuclear capability against critical targets (e.g., weapons of mass destruction, terrorist leadership or operational staging), there has been a search for fast but non-nuclear weapons with worldwide range. If aircraft are not in the target area, it can take many hours or days to put a bomber onto target.
The Conventional Trident Program of putting precision non-nuclear warheads on modified Tridents is generally seen as the quickest interim U.S. approach to this capability.