"It's an overlooked record I think. They were in the midst of breaking up. They were writing separately, and here you can really tell the differences between the Lennon–McCartney and George Harrison songs. What I find really interesting about the record is how it's not really polished. 'Glass Onion' is as unique a song as I've ever heard, and with self-reference: 'I told you about Strawberry Fields', 'the walrus was Paul'; I mean all that stuff! It refers to things the fans were talking about. It's a spectacular album. It doesn't connect like Abbey Road or Let It Be anywhere near as fast because the songs are all over the place. In the days when album covers and packaging meant so much, it was just a brave statement to say it doesn't have a title and leave it white. There is no title anywhere on the record, that's fantastic! Just the solo photos of the band inside. It's a strange record."

"I listen to this record all the way through - even 'Moby Dick'. To me it encapsulates the Led Zeppelin sound, because the engineering on it is so magnificent. The fact that a four-piece band can sound so vast. Obviously there are great tracks on III and IV. But I feel that II is the most complete album. It's amazing to find out they recorded it mostly on tour. Extraordinary. It sounds like it was recorded in one room. I think it's accounted for by the fact they just sound like that. They just sound that magnificent. I was not a huge fan of the first album. I remember reading the story about how, I think it was Glyn Johns again, the story about him playing it to George Harrison, and George Harrison didn't really get it. I wonder if he had played him Zeppelin II he'd have got it. I is not my favourite. On II it felt fully realised. They'd pulled away from that influence of blues; it was still there, but they'd merged it into their own thing. Which again I think is something that people don't associate with Simply Red – we've been enormously influenced by African American music, but we've been influenced by it from a different era. The marriage between black and white started with Bing Crosby and Frank Sinatra and George Gershwin and all these people that ran through music, right through to Elvis, to Jagger, to Robert Plant – we've all in our own ways been enormously influenced by African American music. But the real thing to celebrate is that we made something different out of it. We didn't just copy it. The British especially turned it into something else. It became what we now know as rock music. The Beatles and the Stones are the people who can justifiably claim to have invented what we know as rock music. Not rock & roll, not R&B, not blues, but rock. And that is something to celebrate."