Four versions of this episode exist. Besides the final broadcast version there was also a trial pilot run-through that was not broadcast initially due to technical problems. The 2006 DVD release "Doctor Who: The Beginning" contains an unedited version of this pilot, with several different takes of the TARDIS sequence. A specially made re-edited version of the pilot is included for the first time in this set, using the best takes and digitally manipulating others to remove errors. Previously, an alternate edit of the pilot -- which included dialogue and prop errors -- was broadcast on the BBC and released on VHS.