UNITED KINGDOM — The U.S. military plans to allocate more than $4 billion for upgrades to its military and intelligence bases in the United Kingdom, according to official documents. These plans include the construction of new bunkers intended for nuclear weapons storage in Suffolk.

These modernization plans were detailed in papers presented at a military engineering conference and in documents submitted to the U.S. Congress, which outlined Pentagon expenditures. Presentation slides from a March conference by members of the Air Force Installation and Mission Support Center confirmed that the value of current planning, design, and construction projects at American bases in the U.K. amounts to $4.2 billion. An additional $1.3 billion was characterized as being in draft status. A spokesperson for the center stated that some of the total funding included money from a NATO fund that finances military construction projects, although the exact amount from this fund had yet to be determined. The spokesperson added that the United States routinely upgrades its military facilities in allied nations, and unclassified administrative budget documents often accompany such activities.

More than $1.6 billion is allocated for spending at RAF Lakenheath in Suffolk, the largest American base in the U.K. Documents suggest this expenditure encompasses new infrastructure to house a nuclear arsenal, which is returning to RAF Lakenheath after nearly two decades. The U.S. previously stored nuclear weapons at RAF Lakenheath during the Cold War, and it is believed they were removed in 2008. Pentagon documents indicate that new facilities at RAF Lakenheath will feature reinforced shelters, enhanced security, and accommodation for additional personnel, to be used for storing the latest generation of nuclear bombs.

Another $1.1 billion is earmarked for Mildenhall airbase, also in Suffolk. Covert forces based at Mildenhall are tasked with flying special operatives into territories across Europe and Africa. An unspecified portion of the $1.1 billion at Mildenhall will fund the construction of purpose-built facilities for special forces aircraft. The Pentagon stated that these new facilities would enable special forces to react more rapidly in a crisis.

Nearly $500 million is planned for RAF Fairford in Gloucestershire, where the Pentagon is funding the completion of a new large hangar complex and the renovation of houses to accommodate aircrew. The U.S. is also spending $163 million at Menwith Hill in the Yorkshire Dales, a U.S. base that is part of a network of electronic spying stations. The documents did not elaborate on what the funding at Menwith Hill would support. The modernization plans also include upgrades to facilities to support covert units running secret operations.