page_title: Harold Macmillan
section_title: Nuclear weapons
hierarchical_section_title: Harold Macmillan / Prime Minister (1957–1963) / First government, 1957–1959 / Nuclear weapons
caption_attribution_description: "The first British Hydrogen bomb is dropped near Christmas Island"
context_page_description: Maurice Harold Macmillan, 1st Earl of Stockton, OM, PC, FRS was a British Conservative politician who served as Prime Minister of the United Kingdom from 1957 to 1963. Dubbed "Supermac", he was known for his pragmatism, wit and unflappability.
  Macmillan served in the Grenadier Guards during the First World War. He was wounded three times, most severely in September 1916 during the Battle of the Somme. He spent the rest of the war in a military hospital unable to walk, and suffered pain and partial immobility for the rest of his life. After the war Macmillan joined his family business, then entered Parliament at the 1924 general election for the northern industrial constituency of Stockton-on-Tees. After losing his seat in 1929, he regained it in 1931, soon after which he spoke out against the high rate of unemployment in Stockton-on-Tees, and against appeasement. Rising to high office during the Second World War as a protégé of wartime Prime Minister Winston Churchill, Macmillan then served as Foreign Secretary and Chancellor of the Exchequer under Churchill's successor Sir Anthony Eden.
context_section_description: In April 1957, Macmillan reaffirmed his strong support for the British nuclear weapons programme. A succession of prime ministers since the Second World War had been determined to persuade the United States to revive wartime co-operation in the area of nuclear weapons research. Macmillan believed that one way to encourage such co-operation would be for the United Kingdom to speed up the development of its own hydrogen bomb, which was successfully tested on 8 November 1957.
  Macmillan's decision led to increased demands on the Windscale and (subsequently) Calder Hall nuclear plants to produce plutonium for military purposes. As a result, safety margins for radioactive materials inside the Windscale reactor were eroded. This contributed to the Windscale fire on the night of 10 October 1957, which broke out in the plutonium plant of Pile No. 1, and nuclear contaminants travelled up a chimney where the filters blocked some, but not all, of the contaminated material. The radioactive cloud spread to south-east England and fallout reached mainland Europe. Although scientists had warned of the dangers of such an accident for some time, the government blamed the workers who had put out the fire for 'an error of judgement', rather than the political pressure for fast-tracking the megaton bomb.
  Concerned that public confidence in the nuclear programme might be shaken and that technical information might be misused by opponents of defence co-operation in the US Congress, Macmillan withheld all but the summary of a report into the fire prepared for the Atomic Energy Authority by Sir William Penney, director of the Atomic Weapons Research Establishment. While subsequently released files show that 'Macmillan's cuts were few and covered up few technical details', and that even the full report found no danger to public health, but later official estimates acknowledged that the release of polonium-210 may have led directly to 25 to 50 deaths, and anti-nuclear groups linked it to 1,000 fatal cancers.
  On 25 March 1957, Macmillan acceded to Eisenhower's request to base 60 Thor IRBMs in England under joint control to replace the nuclear bombers of the Strategic Air Command, which had been stationed under joint control since 1948 and were approaching obsolescence. Partly as a consequence of this favour, in late October 1957 the US McMahon Act was eased to facilitate nuclear co-operation between the two governments, initially with a view to producing cleaner weapons and reducing the need for duplicate testing. The Mutual Defence Agreement followed on 3 July 1958, speeding up British ballistic missile development, notwithstanding unease expressed at the time about the impetus co-operation might give to atomic proliferation by arousing the jealousy of France and other allies.
caption: First successful British H-bomb test—Operation Grapple X Round C1, which took place over Kiritimati
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