Both Britain and the United States have now unveiled the number of nuclear weapons in their arsenal as part of a nuclear arms agreement.
For the first time, Wednesday, Britain publicly disclosed that it has a stockpile of 225 nuclear warheads.
Earlier this month, the Obama administration made a similar announcement that the U.S. has 5,113 nuclear warheads and "several thousand" more retired warheads waiting to be junked.
The revelations are part of a global initiative for nuclear transparency in hopes of stopping the spread of atomic weapons.
"We believe that the time is now right to be more open about the weapons we hold," Foreign Secretary William Hague told the House of Commons Wednesday. "We judge that this will assist in building a climate of trust between nuclear and non-nuclear weapons states and contribute, therefore, to future efforts to reduce the number of nuclear weapons worldwide."
Never before have countries gone public about their nuclear stockpiles.
Countries that don't possess nuclear weapons have long demanded more openness from the U.S., Britain, France, Russia and China -- the nuclear weapons states.
In the announcement of its nuclear arsenal, Britain stressed that it only holds 1 percent of the world's stock of nuclear weapons and "the explosive power of Britain's stockpile has been reduced by something like 75 percent since the end of the Cold War."