The Sex Pistols have released a lost demo recording of a track penned by the late Sid Vicious.
The bass player and punk icon reportedly wrote the controversial track, Belsen Was a Gas, before he signed on to become a member of the group.
According to, the band only recorded the track with pal Great Train Robbery kingpin Ronnie Biggs on vocals. The new demo features John Lydon, aka Johnny Rotten, on lead vocals.
The track will appear on the upcoming 35th anniversary box set reissue for Never Mind The Bollocks, Here's The Sex Pistols, which is released on 25 September (12).
The provocative tune refers to the Bergen-Belsen concentration camp operated by the Nazis during World War Two.