Can anyone tell me why P.Floyd is prog?

Dick Heath wrote: A number of us old timers were baffled when both Rush and Pink Floyd found their way on to Channel Four prog top 10 groups not so long ago. It wasn't America heard DSOTM that the band was called prog, as opposed to psychedelia. So as to being more progressive than other bands, well until they over got over the loss of Syd Barrett it was felt they spent half a decade navel grazing, and progressing by a gnat's cock l

With historical restrospect, that seems like nonsense:

"Saucerful..." was a kind of "Piper 2", but the writing does show marked progression - the title track alone is practically pure Prog Rock, not just a psychedelic jam.

"Ummagumma" represents a major leap forward in terms of the experimentation on sides 3 and 4 - no matter what the band think about it now, I hear it as genius - pure stream of consciousness music (albeit with a smorgasbord of ego...).

"Atom Heart Mother" is very different again - I'm not totally convinced by it, but there are deliberate attempts to do different things and use new sonic soundscapes.

"Meddle" is a pure masterpiece - especially "Echoes", and a stunning progression from the <"Ummagumma" style.

Then there's the "Live at Pompeii" film, which I still find to be a stunning live performance to this day, not to mention "More", "Zabrieski Point" and "Obscured by Clouds"... OK, I did mention them, and they are all somewhat sub-par - but clearly show what the band were capable of when they were only ticking over. I generally don't count them as "bona fide" Floyd albums since they're sound tracks. They were handy doodle pads for later albums - and an interesting insight into the way they changed their collective approaches to composition.

Which brings us to "DSOTM" - which, of course, was performed live many, many months before the band hit the studio.

But that's just a retrospective perspective...