The United Kingdom submitted its annual declaration of holdings of civilian plutonium and HEU that describes its stock as of December 31, 2011 - INFCIRC/549/Add.8/15.

According to the document, the U.K. had 113.3 tonnes of separated unirradiated plutonium at the reprocessing facilities, 2.3 tonnes in unirradiated MOX fuel and 1.2 tonnes in the MOX fuel manufacturing process. Additional 1.4 tonne of unirradiated plutonium is "held elsewhere." These numbers apparently include the 4.4 tonnes of plutonium that the United Kingdom declared as excess to its national security needs.

Of this total of 118.2 tonnes, 27.9 tonnes belonged to foreign countries. In addition, the U.K. had 0.9 tonnes of its plutonium outside of country. No material was in transit. Compared to the end of 2010, the amount of plutonium increased by 3.4 tonnes - from 114.8 to 118.2.

In addition, the United Kingdom declared 8 tonnes of plutonium in spent fuel held at reactor sites, 24 tonnes - in spent fuel at reprocessing plants awaiting reprocessing (25 tonnes were reported in this category in 2010), and less than 500 kg - in spent fuel held elsewhere.

The declaration also contains information about civilian HEU holdings - the United Kingdom had 1400 kg of the material, down from 1404 in 2009. Of this HEU, 346 kg is at fabrication plants, 912 kg - at laboratories and research facilities, 10 kg - irradiated HEU at civilian reactor cites, and 131 kg - irradiated HEU at other sites. This numbers didn't change since the 2010 declaration.