Hear Johnny Rotten vocals on Sex Pistols' demo track Belsen Was a Gas

Hear Johnny Rotten vocals on Sex Pistols' demo track Belsen Was a Gas Famous rockers Sex Pistols have released a recently-recovered studio version of their thought to have been lost long time ago. Titled "Belsen Was a Gas", the track was originally penned by Sid Vicious and features the vocals of frontman Johnny Rotten.

On top of that, the controversial track was written about the infamous Nazi concentration camp and can be heard after the jump. The demo has now been restored in the rehearsal room on Denmark Street, and will feature on the 35th anniversary deluxe reissue of the band's classic LP Never Mind The Bollocks, Here's The Sex Pistols due on September 25th.

The only studio recording made of the track was a 1978 version with train robber and criminal Ronald Arthur "Ronnie" Biggs on vocals. During this time, the band played a version of the track on their 2008 reunion tour, but it was renamed "Baghdad Was A Blast" in protest at the US and UK's invasion of Iraq.

Sex Pistols' new single "Belsen Was a Gas"

Speaking of the track, soundman on the recording John 'Boogie' Tiberi said to NME: "It really shouldn't have to be said but that's Sid on bass. It was very clumsy, no monitors, sound insulation was non-existentm."

"I think they all enjoyed doing it outside of the Wessex environment, which had by then become quite oppressive.

"When I played it to (Pistols producer) Chris Thomas he probably thought I was barmy and couldn't understand the reverb vocal, but that's the way John wanted it," he added.

"I thought it was good as a kind of sketch idea."