Following the report of the [[Strath Committee]] in 1955, the British government developed contingency plans for the continuity of government. This included construction of the [[Central Government War Headquarters]] (CGWHQ), codenamed BURLINGTON, at [[Corsham]]. As planned, it would have been a "reserve [[Whitehall]]" where the central government could be moved in an emergency and, hopefully, survive a nuclear attack. As nuclear weapons became more powerful and [[intercontinental ballistic missiles]]s became more of a threat than manned [[bomber]]s, the concept of concentrating central government in a single ___location became flawed. Instead government would be dispersed around the country with just core functions at CGWHQ. The [[Cuban Missile Crisis]] of 1962 prompted a radical rethink of continuity plans.<ref name="herald">{{cite news|url=http://www.heraldscotland.com/news/15039649.How_Scotland_and_three_CalMac_ferries_played_a_crucial_part_in_nuclear_planning/|title=How Scotland and three CalMac ferries played a crucial part in nuclear planning|publisher=The Herald|date=22 January 2017}}</ref> Part of the thinking was that the Precautionary Period ahead of nuclear war, or a conventional war in Europe culminating in nuclear war, might only last 2-3 days rather than the 7 days originally planned, so it would not be possible to fully staff CGWHQ with 4,000 people in time.<ref name="Hennessy">{{cite book|title=The Secret State: Preparing For The Worst 1945 - 2010|page=141|author=Peter Hennessy|publisher=Penguin|year=2014|isbn=0141979208}}</ref>
PYTHON became active on 1 May 1968 and described in the 1968 update to the Government War Book.<ref>CAB 21/5655 Government War Book, The National Archives</ref>
