the Cold War, MI5 had an officer at the BBC vetting editorial applicants. During World War II 'subversives', particularly suspected communists such as the folk singer Ewan MacColl, were banned from the BBC. The personnel records of anyone suspicious were stamped with a distinctively shaped green tag, or "Christmas tree;" only a handful of BBC personnel staff knew what the 'Christmas trees' meant. 1930s: Commercial radio controversy Because the BBC had become both a monopoly and a non-commercial entity, it soon faced controversial competition from British subjects who were operating leased transmitters on the continent of Europe before World War II, to broadcast commercial radio programmes into the United Kingdom. John Reith, who had been given powers to dictate the cultural output of the BBC, retaliated by leading the opposition to these commercial stations. Controversy spilled over into the press when the British government attempted to censor the printing of their programme information. The pressure was created by the success of these stations. 1930s onwards: Broadcasting jazz In her biography of her father, My Father: Reith of the BBC, Reith's daughter Marista Leishman said that he banned the playing of jazz music on the BBC, and that he wrote in his diary that "Germany has banned hot jazz and I'm sorry that we should be behind in dealing with this filthy product of modernity." In 2010, 19 MPs supported an early day motion “That this House is concerned that BBC Radio devotes such little broadcasting time to jazz” A 2015 Jazz Services study reported that jazz as a percentage of total music output was only 1.74% on Radio 2 and 3.62% on Radio 3. In 2019 the BBC announced cutbacks in jazz programming at the BBC. In January 2023, it was reported that the jazz page would no longer appear in every edition of BBC Music Magazine. Post-war 1950s: Claimed involvement in Iranian coup d'état A BBC Radio 4 documentary in 2005 claimed that it had evidence that a radio newsreader inserted the word "exactly" into a midnight timecheck one summer night in 1953, as "It is now exactly midnight", a code word to the Shah of Iran that Britain supported his plans for a coup. The shah had selected the word, the documentary said, and the BBC broadcast the word at the request of the government. Officially, the BBC has never acknowledged the code word plot. The BBC spokesman