'Stairway to Heaven,' one of rock's most enduring tracks and the bane of anyone having to man the tills at guitars shops around the world, may owe its place in history thanks to its cigarette-break-friendly length.

Led Zeppelin's most famous song became the rock radio staple it did because, the band's biographer claims, it was the perfect length for a DJ to take a crafty fag break.

"The song became successful by accident," Charles R. Cross told the New York Post. "[I] had 100 DJs swear to me that they only played the song because they needed a long break to go and smoke a cigarette. If it had been a minute shorter, you couldn't have smoked a full cigarette. If it had been a minute longer, it would have been too long."

'Stairway to Heaven' was never released as a single -- Led Zeppelin didn't do singles -- but nonetheless became one of US radio's most broadcast songs.

But the song is something of an albatross for Led Zeppelin, Cross told the paper it could possibly be one of the reasons the band's oft-rumoured reunion has stalled. While Jimmy Page still loves playing the song's foot-on-monitor guitar solo, singer Robert Plant, apparently, can't stand his band's biggest hit.

"Page's love of the tune seemed to go in inverse proportion to Plant's hate," Cross said.

Stairway. Denied.