KILLERS, BEASTS, SLAVES, SONS. SOULS...

With Iron Maiden celebrating their 50th anniversary this year, we talk to all the members of the band and look back over the successes, trials, tribulations, thrills, spills and genre-defining records of the longest-running and arguably greatest heavy metal band of them all.

- Paul Elliott

"When you start out as a band, you don't think further than your first album. You dream about touring the world. Anything else is a bonus."

He wrote songs that shaped the sound of heavy metal in the early 80s, among them Phantom Of The Opera, Wrathchild, Run To The Hills, The Number Of The Beast and The Trooper. But when Iron Maiden bassist Steve Harris thinks back to the very first song he wrote - in the early 70s, when he was aged just 16 - he can only laugh at the absurdity of it all.

"My first band was called Influence," he says. "Then we changed the name to Gypsy's Kiss, which is Cockney rhyming slang for you know what. And I wrote this song that had an awful title: Endless Pit.

Which isn't Cockney rhyming slang, but it should be." The title wasn't his. The blame, he says, falls on his school friend Dave Smith, who wrote the song's lyrics. But forgetting the title there was something about that song - something that would prove hugely significant in the life of Steve Harris. Later, the main riff in Endless Pit was developed into a new song called Innocent Exile, which Harris performed with Smiler, the band he joined after Gypsy's Kiss broke up. He also took that song into the band he formed in 1975. The band in which his singular vision would be fully realised, the band he has led ever since.

Innocent Exile was, in essence, the first Iron Maiden song. The first step on the road to world domination for one of the greatest heavy metal bands of all time.

This year, Iron Maiden celebrate their 50th anniversary with the Run For Your Lives tour, in which they will perform classic material from 1980 to 1992.