The Bletchley Circle is a television mystery drama series, set in 1952–53, about four women who worked as codebreakers at Bletchley Park. Dissatisfied with the officials' failure to investigate complex crimes, the women join to investigate for themselves.The first series of the miniseries, produced for ITV, was originally shown in the UK in 2012 and premiered in the U.S. in April 2013, on PBS. A second series was broadcast on ITV in January 2014 and on PBS in April 2014. Both series were later aired by Australia's ABC TV. The series was distributed worldwide by Kew Media.The programme was not renewed for a third series. However, in 2018, a spinoff series titled The Bletchley Circle: San Francisco was announced by ITV and BritBox.