On 1 November 2013, it was reported that Gambaccini had been arrested on suspicion of historical sexual offences as part of an investigation by Operation Yewtree in the United Kingdom. He was released on bail and his spokesman said that he denied the allegations. It was announced on 10 October 2014 that no charges would be brought. Giving evidence to the House of Commons Home Affairs Select Committee on 3 March 2015, Gambaccini said he believed he was used as human "fly paper" to encourage other people to come forward and make allegations against him.
In 2013, Gambaccini claimed that he had been highlighted as a potential security risk by the BBC earlier in his career due to his sexuality, with a symbol resembling a Christmas tree on the cover of his personnel file: "It meant you were 'as camp as Christmas' and thus a potential security risk." In fact, the symbol was a general indication that the subject should not be "promoted or transferred" without reference to the department responsible for security vetting, due to left-leaning sympathies.