John Entwistle, bassist with legendary rock group The Who, died when a "significant amount of cocaine" brought on a heart attack, a coroner has said.

The coroner in Clark County, Nevada, ruled that his death was accidental and was not an overdose.

You've got a lethal drug on board at the time you have a bad heart - that's a bad combination

Ron Flud Coroner

But he said Entwistle died when cocaine caused the contraction of coronary arteries that were already damaged by heart disease.

Entwistle, 57, was found dead in his hotel room in Las Vegas on the eve of the rock group's United States tour in June.

The coroner, Ron Flud, said the exact amount of cocaine taken was unknown.

"It's not like alcohol," he said. "There's no way we can put a number on it.

His funeral was held in Gloucestershire on 10 July

"You've got a lethal drug on board at the time you have a bad heart. That's a bad combination."

Entwistle, known as "the Ox", was reportedly taking medication for a heart condition.

The immediate cause of death was "ischemic heart disease" due to "coronary atherosclerosis", a statement from Mr Flud's office said.

Officials from the Hard Rock Hotel, where the musician's body was found, and the band's record company declined to comment.

Clark County District Attorney Stewart Bell said he did not expect any criminal charges to be brought.

The Who decided to continue their tour

"From a legal point of view, there isn't anything to be done because we don't have anybody else who might be responsible," he said.

Entwistle's sudden death came almost 25 years after The Who's original drummer, Keith Moon, died of an accidental drug overdose.

Entwistle was a founding member of The Who, who formed in London in 1964 and were one of the leading rock bands through the 1960s and 70s scoring hits with songs like Pinball Wizard and My Generation.

'Spirit of rock'

After his death, the two remaining band members, Pete Townshend and Roger Daltrey, began the US tour with a replacement bass player.

"He was the true spirit of rock n' roll and he lives on in the music we play," Roger Daltrey said at the first gig.

Entwistle's funeral took place near his home in Stow-on-the-Wold, Gloucestershire, on 10 July.

The musician's website said a memorial service would take place in London later in the year, and fans would be invited to attend to celebrate his life.