"Saviour" is a song written by Adele and Paul Epworth for Adele's sophomore album, 21.  It is one of the few known cuts from any of her albums, let alone 21. It is unknown why the track was cut from the album. It may, however, appear on a future album, as Adele has stated that she is re-recording "Never Tear Us Apart" for her third album; this track was also originally cut from 21.
"Saviour" was rumored to have been cut from the album due to its themes not fitting well with the rest of the album. Paul Epworth did speak of its title possibly being used for inspiration in some of the lyrics in "Turning Tables", but even he has remained unsure of this.
Epworth confirmed that Adele considered performing the song on her Adele Live tour, which did not happen, and he also told a fan that it was being considered for future records and he wouldn't be surprised to see its release at some point. 
- EMI Blackwood Music, Inc.
- Universal Songs of Polygram International, Inc.