I like change and I like contrast.

There is no way I would play guitar like a tour de force like I did in Led Zeppelin. John Bonham, phenomenal drummer, young man with his technique, but do you think he would ever have the opportunity to play like that in another band? Of course he hadn't.

I think it was that we were really seasoned musicians. We had serious roots that spanned different cultures, obviously the blues.

That's the music that I play at home all the time, Joni Mitchell. Court and Spark I love because I'd always hoped that she'd work with a band. But the main thing with Joni is that she's able to look at something that's happened to her, draw back and crystallize the whole situation, then write about it. She brings tears to my eyes, what more can I say? It's bloody eerie. I can relate so much to what she says. "Now old friends are acting strange/They shake their heads/They say I've changed."

Right from the first time we went to America in 1968, Led Zeppelin was a word-of-mouth thing. You can't really compare it to how it is today.

There's so many different styles and facets of the 360-degree musical sphere to listen to. From tribal to classical music, it's all there. If the bottom was to sag out of that, for God's sake, help us all.

I can tell how far I ought to be going, I know how to get there, all I've got to do is keep playing.