President Barack Obama has quietly agreed to a secret ten-year deal with the United Kingdom to collaborate on nuclear weapons technology and materials—sparking concern among advocates of nuclear disarmament, who say the countries should be cooperating to dismantle—not develop—their arsenals.

The deal would extend the terms of a "Mutual Defense Agreement" struck in 1958 between the U.S. and the U.K. that has been renewed regularly since it was formalized, with the most recent renewal in 2004. The agreement has played a critical role in building up the nuclear arsenals of both countries and stems from nuclear cooperation dating to the 1940s. Robert Alvarez, senior scholar at the Institute for Policy Studies and former senior policy adviser to the secretary of energy under the Clinton administration, told Common Dreams that the latest renewal "will not go into force until a certain amount of time elapses and Congress does nothing to stop it."

President Barack Obama said in a message to Congress issued July 24 that he has signed off on a renewal of the deal that will "permit the transfer between the United States and the United Kingdom of classified information concerning atomic weapons; nuclear technology and controlled nuclear information; material and equipment for the development of defense plans; training of personnel; evaluation of potential enemy capability; development of delivery systems; and the research, development, and design of military reactors."

Obama notes that amendments have been added to the agreement regarding "nuclear threat reduction, naval nuclear propulsion, and personnel security." However, he does not clarify the changes, and the full details of the deal are kept secret in both the U.S. and the U.K.

The U.K.-based watchdog Nuclear Information Service warns in a recent report that the deal with facilitate developments including the creation and stockpiling of nuclear warheads and submarines and the creation of new nuclear research. According to the organization, the "relationship and activities" that the deal enables are not compatible with the obligations of either country under the Treaty on the Non-Proliferation of Nuclear Weapons.

Alvarez said that the extension of the deal is "business as usual—standard boiler plate stuff" and is likely to breeze through Congress.

However, nuclear 'business as usual' has fallen under increasing criticism, with people around the world pushing their governments to move away from nuclear weapons. President Obama said in a a 2009 speech that nuclear non-proliferation would be a key tenet of his foreign policy, declaring, "I state clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons."

But in his message about the deal, Obama takes the ongoing role of a "nuclear deterrent" as a given for both the U.S. and the U.K.: "The United Kingdom intends to continue to maintain viable nuclear forces into the foreseeable future. Based on our previous close cooperation, and the fact that the United Kingdom continues to commit its nuclear forces to the North Atlantic Treaty Organization, I have concluded it is in the United States national interest to continue to assist the United Kingdom in maintaining a credible nuclear deterrent."

A report by the Stockholm International Peace Research Institute found that, as of the beginning of 2014, the U.S. had 7,300 nuclear warheads, with the U.K. possessing 225.

The deal has whipped up controversy in the U.K., where—as Richard Norton Tailor reports for the Guardian—it is critical to the highly controversial Trident nuclear weapons systemwhich is fiercely opposed by anti-nuclear advocates.

According to the Nuclear Information Service report, "The nuclear relationship between the USA and the US is not a partnership of equals. The UK relies on unique US facilities and capabilities for support to the extent that its nuclear weapons programme cannot be regarded as technically independent from the USA."