The band had arrived in Northern Ireland at a time when The Troubles were at their height. In fact, violent riots were going on just a few streets away during the concert.
After a stunning version of "Dazed And Confused" came the new unheralded song that at first intrigued and then swept away the audience. The magic and pathos of the piece seemed to be even more relevant in the warring atmosphere of the times. During the performance, Page played a double- necked guitar utilising both 12 and six strings. The finger-picked contrapuntal guitar intro became one of rock's best known phrases, beloved of all aspiring guitarists.
On the flight home, Page explained that the intro to "Stairway" on the record also featured wooden recorders played by John Paul Jones. "We can't reproduce them on stage, but the acoustic guitars come off well. The words are brilliant - they are the best Robert has ever written."
The song had been assembled through a process of trial and experiment, but came together quite quickly. At the recording session they had put down a rehearsal version on tape first, which helped put the words into focus. Page later said: "I had `Stairway' tucked away on my cassettes. Robert arrived at Headley Grange quite late in the day and I'd actually got all the musical part together from beginning to end. Robert came in with 60 per cent of the lyrics off the cuff, which was quite something. He was listening to the music, sitting on a stool by a log fire and jotting away, and suddenly he came out with all these lyrics."
The crucial moment after the acoustic build up when John Bonham comes in with all drums blazing was a brilliant touch. As Page remembers: "It was an idea I'd used before, to give it that extra kick. `Stairway To Heaven' crystallised the essence of the band. It had everything there and showed the band at its best."
The bulk of the eight-minute piece was recorded at Island Studios in London, rather than at Headley Grange. Page knew it was going to be a complex construction and he needed full studio facilities to complete the production work.
The full impact of the song only really sank in when the album was finally released. Over the following years as the song grew in stature it became the most played track of all time on US radio. In London, it became No1 in Capital Radio's Top Five Hundred, just one of many awards it picked up.
For Page it remains a magical piece of work. In 1982, at a charity concert held in London's Royal Albert Hall, he played it with almost demonic energy. With a cigarette pasted on his lower lip, clutching his guitar, he struggled around the stage, as if literally rebuilding his life before the eyes of an appreciative audience.
Led Zeppelin, `Dazed and Confused' is published by Carlton, price pounds 12.99. For a copy for only pounds 9.99, phone Books by Post, 01624 675 137