Nonproliferation talks entered their decisive phase after the submission of a joint U.S.-Soviet draft to the ENDC on February 21, 1967. One week later, High-Commissioner of the French Commissariat à l’énergie atomique, Francis Perrin, assessed France’s options. It was not “by accident,” he noted, the original five UN Security Council permanent members—the United States, the United Kingdom, France, the Soviet Union, and China—were in line for nuclear-club membership: “…they are the same profound reasons, of a geographical, demographic or other nature, which led to the choice [in 1945] … of the countries with special responsibilities in the maintenance of world peace.” After noting how advances in “India, Israel, Japan, Sweden, and also West Germany” portended the further spread of nuclear weapons—and acknowledging France had itself sought help with its weapon program—Perrin pondered whether proliferation might hasten nuclear disarmament by convincing the superpowers of its merits. In the end, however, fear of a “large and hostile” nuclear-armed PRC made him pessimistic. While he did not advise signing the NPT, it would be “very important” for France to affirm publicly, if unilaterally, “its constant policy since 1958 … not to cede any atomic weapon or any atomic explosive device to a country which does not possess it, and not to help any such country to manufacture them.” He dismissed internal opposition toward the NPT as defensive—"an a posteriori justification of the French decision to constitute an atomic armament." More significant was the likelihood West Germany would gain its own atomic arsenal, jeopardizing France’s “dominant political position among the Europe of the Six” members of the European Communities and reviving Cold War tensions in Europe. He finished with an eye-opening analysis of how the Kosygin proposal for nuclear-weapon states to extend negative security guarantees to non-nuclear-weapon states’ signatory to the NPT would not impede the use of French nuclear armaments against a West German blitzkrieg backed by the United States.

By the early summer of 1967, Foreign Secretary George Brown felt compelled to comment that "if the situation should arise in which there is a direct confrontation between the United States and Russians on one side—and the members of EURATOM on the other, on the issue of the acceptability of EURATOM safeguards we should have to consider our position very carefully: the whole success of our European policy might depend on the choice we made. For the present it should therefore be a major aim of our policy at Geneva to see that things do not reach such a state." This came only a week after Wilson formally launched the UK's bid to become a member of the EEC, and two days after De Gaulle cast doubt on Britain's fitness to join the community.

Two "Notes for the Record" from March 1, 1967, describe the vigorous discussions between senior UK government figures, including Harold Wilson, Foreign Secretary George Brown, Minister of State for Foreign and Commonwealth Affairs Lord Chalfont, and chief scientific adviser to the government Solly Zuckerman. Brown argued that "our posture on the matter should be distinctively European rather than one of supporting the United States against other European countries." Wilson was even more explicit, stating that "our approach should be that of a European power discussing the matter with European partners and not seeking to fight American battles." Wilson was keen to let Washington take the lead so that his government might avoid upsetting the French, as had happened with the debates over De Gaulle's 1966 withdrawal from the NATO command structure.

Two "Notes for the Record" from March 1, 1967, describe the vigorous discussions between senior UK government figures, including Harold Wilson, Foreign Secretary George Brown, Minister of State for Foreign and Commonwealth Affairs Lord Chalfont, and chief scientific adviser to the government Solly Zuckerman. Brown argued that "our posture on the matter should be distinctively European rather than one of supporting the United States against other European countries." Wilson was even more explicit, stating that "our approach should be that of a European power discussing the matter with European partners and not seeking to fight American battles." Wilson was keen to let Washington take the lead so that his government might avoid upsetting the French, as had happened with the debates over De Gaulle's 1966 withdrawal from the NATO command structure.

Before and after de Gaulle's November 1967 veto of Britain's second EEC application, Britain's position in Europe and its relationships with existing EEC states shaped the UK's role in the NPT negotiations. Prior to 1967, London canvassed opinion in EEC capitals, particularly in Bonn. As the NPT negotiations wound their way through the Eighteen Nation Committee on Disarmament (of which the United Kingdom was a member) in 1967, British representatives reported deep-seated concerns in Bonn, Brussels, the Hague, Luxembourg City, Paris, and Rome that a non-proliferation agreement might threaten the continued functioning of EURATOM, namely that its power might be subsumed into the IAEA, opening non-nuclear-weapon states (NNWS) up to commercial espionage conducted by inspectors representing the nuclear-weapon states (NWS).

Alfonso Garcia Robles used his address to describe the progress in the negotiations of the Treaty of Tlatelolco. For him, this treaty included the most ambitious definition of nuclear weapons compared to existing nuclear governance texts. Another innovation was the reliance on the International Atomic Energy Agency’s safeguard system to monitor compliance. Garcia Robles also explained that Latin American delegations were almost in consensus about the Treaty of Tlatelolco text except for a couple of issues. Countries did not agree on defining the territory where the treaty would apply and when it would enter into force. The Ambassador also took this opportunity to explain the Latin American efforts to obtain negative security assurances from China. Moreover, he reminded delegates that the success of the NPT would depend on balancing obligations for nuclear and non-nuclear-weapon states. Mexican representatives argued that it was necessary to include more ambitious disarmament goals in the draft of the NPT. However, they rejected proposals to condition the approval of the NPT on the existence of concrete steps toward disarmament

The Japanese Foreign Ministry outlines areas of where Japan's views and positions are evident in the final text of the NPT, including the sections on disarmament, the security of non-nuclear weapon states, the peaceful uses of nuclear energy, and procedural issues.

This memo discusses several amendments proposed by various non-nuclear countries during the First Committee of the UNGA, and the Soviet delegation's amenability to adding amendments and clarifications to the NPT so long as the essence of the Treaty is not altered or undermined. Some of the topics of the proposed amendments include the strengthening of sharing nuclear technology and research on nuclear energy and other peaceful uses of the atom and international observation as it pertains to peaceful nuclear explosions. Attention is also paid to when further negotiations on peaceful nuclear explosions will take place, relaying the difference in Soviet and American opinions on what the optimal timing of those negotiations would be but, ultimately, the Soviet government's desire, first and foremost, to have the NPT go into effect as soon as possible.

This agreement details the responsibilities of governments party to the NPT and the IAEA in accordance with the Treaty, including transparent and prompt notifications to the IAEA about any nuclear materials, facilities, and transfers of nuclear materials within a state's territory. Transparency about nuclear materials is reciprocal, with the NPT obligating the IAEA to send an inventory list to the governments every 12 months or upon request. Additionally, this document details safeguard procedures, including IAEA inspections (and the responsibility of governments to provide inspectors with the necessary visas). This document also states that the present agreement will be in force indefinitely, and a state can cease to abide by its terms if it ceases to be a participant in the NPT per Article X on the right of states to withdraw.

This document references the draft model agreement of non-nuclear weapons states, instructing both the Soviet MFA and the Ministry of Medium Machine Building (which supervised the Soviet nuclear industry) to conduct negotiations with the US to solidify this agreement. After negotiating with the Americans, they are instructed to make sure that the project is approved by the IAEA Board of Governors and inform socialist UN member states and the GDR about the Soviet position on the NPT.