Each series covers topics that begin with a different letter of the alphabet; for example, the first series covered topics whose word began with “A”. Thus it is referred to as “Series A” instead of “Series One”. The first episode, “Adam”, was premiered on BBC Two on 11 September 2003. From the second to the fifth series, episodes were aired each week on BBC Two; the second and subsequent episodes were shown first on BBC Four in the time-slot after the previous episode’s BBC Two broadcast. When the sixth series of QI began in 2008, the show moved to BBC One and the broadcasting of episodes on BBC Four was replaced in favour of an extended repeat broadcast on BBC Two the following day, titled QI XL.
Here is a playlist of all the episodes that have been uploaded so far, enjoy.