The Tenth Planet of malevolent cyborgs that became a recurring adversary in later "Doctor Who" stories. The "tenth planet" in the title makes reference to a fictional lost planet in Earth's Solar System; at the time of production, the Solar System was generally held to consist of nine planets, prior to the redesignation of Pluto as a minor planet. "The Tenth Planet" is an incomplete "Doctor Who" serial – one of many serials that were affected by the BBC's policy of wiping archived programmes in the 1960s and 70s. Only three of the four episodes are currently held in the BBC archives; the
Gustav Holst and you've got to conduct'." There was a burst of activity to get things ready in time. The girls at St Paul's helped to copy out the orchestral parts, and the women of Morley and the St Paul's girls learned the choral part in the last movement. The performance was given on 29 September to an invited audience including Sir Henry Wood and most of the professional musicians in London. Five months later, when Holst was in Greece, Boult introduced "The Planets" to the general public, at a concert in February 1919; Holst sent him a long letter full of