And he says his biggest regret about the band’s career is the years they used cocaine, which eventually resulted in the firing of Ozzy Osbourne.
Asked if the band’s Satanic overtones came about, Iommi tells the BBC: “When we did the first album the record company did the cover, and that’s what done it – the inside was an upside-down cross and that’s what started everybody off.”
The guitarist denies the suggestion that the imagery is simply misleading, saying: “We believe in what we did. You can only judge by: we’ve been in it for 45 years. You answer it.”
Sabbath have been linked to murders and suicides by the mainstream press for decades, with bassist Geezer Butler’s lyrics frequently cited as inspiration for criminal acts. But Iommi says: “All I do is create music. I don’t create anything to destroy people or to upset anybody. It’s helped more people.
“The lyrics are what happens in the world. What Geezer would write about is what he’d seen and felt and what we were going through. Geezer said to me he had to write powerful lyrics to go with the powerful lyrics. It was probably my fault then!”
The band last week topped the album charts with 13, their first record with Osbourne since 1978′s Never Say Die. He was fired the following year as a result of his drink and drug issues – and Iommi admits that era is the part he most regrets about his career.
“I can’t change it, but there’s things you could have done in a different way,” he says of the years he spent using cocaine. “If I’d known then what I know now I wouldn’t have dabbled to that extent.
“It did a lot of damage. Initially we thought it was great and it was helping us create. When it came to the point we had to replace Ozzy we were in a bad way.”
Asked how the firing was handled, the cancer survivor recalls how drummer Bill Ward took control of the situation. “The drummer did it; he told him. We were going to tell him all together, but Bill stepped in.
“It was a terrible thing to do – but Ozzy wasn’t into it any more and he was doing too much of everything.”
The full HardTalk show is available to UK users via BBC iPlayer until 1am on Friday.