Conservative Party The Conservative Party was one of the two dominant political parties ( the other being the Labour Party ) in the United Kingdom during the 20th and 21st centuries . Several of its leaders had held the office of Prime Minister of the United Kingdom . The Conservatives were in office during the early 1960s . Harold Macmillan served as Prime Minister until his resignation in 1963 . He was succeeded by Sir Alec Douglas - Home . ( AUDIO : " The Pelage Project " ) In 1963 , Barbara Wright was a supporter of the Conservative Party whereas Ian Chesterton supported the Liberal Party . She regarded his politics as " wrong but romantic . " ( PROSE : " Nothing at the End of the Lane " ) In 1964 , the Conservative Party was defeated by Labour in the UK general election and the latter ' s leader Harold Wilson became Prime Minister . In the immediate aftermath of the election , General Peters led a military coup against Wilson ' s government . However , it was defeated by the Intrusion Countermeasures Group . ( AUDIO : " State of Emergency " ) By 1965 , Edward Heath was the Conservative leader . Some of the Conservatives were members of the Monday Club and the rival Sunday Club , the latter similar to the US neoconservative movement . William Heaton , shadow undersecretary to the Minister of Affairs and a Sunday Club member , believed Heath wouldn ' t win the next election . ( AUDIO : " Changing of the Guard " ; PROSE : " Who Killed Kennedy " ) In later years , Wilson ' s position seemed untenable after the failures of the Wenley Moor nuclear research facility in October 1969 and the Inferno Project in February 1970 were publicised by James Stevens in his " Bad Science " series of articles . Wilson called a general election for June 1970 . The Labour Party lost and Heath became Prime Minister . Political observers speculated that the publication of the book version of " Bad Science " had coincided not - so - incidentally with the election . ( PROSE : " Who Killed Kennedy " ) In the 1970s , after a general election , various disenfranchised Tories joined a coalition government with the Liberals , minor fringe parties , and dissident Socialists . This government formed before Jo Grant joined UNIT ( PROSE : " The Devil Goblins from Neptune " ) and in her first year , a Conservative was Defence Minister . He authorised Horatio Chinn to use the Emergency Powers Act against UNIT . ( TV : " The Claws of Axos " ) In 1979 , the Conservatives were once again in office with Margaret Thatcher as Prime Minister . ( TV : " Tooth and Claw " ) Her predecessor was James Callaghan of the Labour Party . ( AUDIO : " The Oseidon Adventure " ) On 9 June 1983 , the Conservatives defeated Labour in the general election in a landslide . ( AUDIO : " Rat Trap " ) The party was still in office in 1987 while Thatcher remained Prime Minister . ( TV : " Father ' s Day " ) By 1984 , the former actor Heathcliffe Bower was a Conservative MP . In an alternative timeline which was later negated by the Fifth Doctor , Bower assassinated Thatcher in that year . ( PROSE : " The Assassin ' s Story " ) As her parents were children of the 1960s , Sam Jones thought that the only methods of acting out open to her were becoming a major drug addict , or joining the Conservative Party . ( PROSE : " Vampire Science " ) According to Rachel Edwards , a Conservative Party conference was filled with white men , and an " all - pervading stench of repressed homosexuality " . ( PROSE : " Head of State " )