Black Sabbath guitarist Tony Iommi has told Metal Hammer that Black Sabbath's headline appearance at the Barclaycard British Summer Time festival at London's Hyde Park might be the British metal institution's final gig.

The July 4 show, the closing date on the band's summer 2014 tour, will see Sabbath headline above Soundgarden, Faith No More, Motorhead and Soulfly on the festival's main stage. And according to Iommi, it could be the end of the road for the legendary band.

"It could be the last ever Sabbath show,” the guitarist admits. “I don't want it to be, but there's nothing really planned touring-wise after that show, so for all we know that could be it really. To be honest I don't want to be touring to this extent too much longer, because it makes me feel so bad.”

Iommi has been undergoing medical treatment since being diagnosed with lymphoma in January 2012. The guitarist completed his treatment in March and is now awaiting an update on his condition.

"I'm at a stage now where I have no support, which means I have to see whether the cancer is coming back or if it's still there or what,” he says. “I just don't know. It's a bit of a worry. After we finish this tour I'll go in and have scan, so we'll see what that shows up.”

"But the show at Hyde Park will a great way to end the European tour,” he says. “It has a really great bill, with a really good mix of people. We haven't made any specific plans as the gig is a way off yet, but I think it'll be special.”