Yesterday I stumbled upon a rather good BBC Four documentary about British progressive rock on Vimeo. Watch or grab it before it's gone. Aside from the groups most everyone knows (or maybe dreads by reputation) - Yes, King Crimson, Jethro Tull, Genesis, ELP - other lesser-known bands get much more than a nod as well, including two of my favorites, Soft Machine and egg (bonus music geek points for naming the tune at 1'40")

As usual in most music documentaries, the sync of music, band incarnations, and footage doesn't always align (especially at 82'10") correctly, but it's a good primer nonetheless: Don't miss the priceless clip of soft machine's inscrutable Mike Ratledge demonstrating his non-stop note technique on the Lowery organ, Peter Gabriel in an oversized flower ruff, and everyone looking young and vegan-thin.

"Success is buried in the garden of failure," says ex-Yes keyboardist Rick Wakeman, in a postscript to time where a band could title side one of a double LP "The Revealing Science of God" and get away with it. Have the major corporate record labels been so bold to release such unhesitatingly arty and brave music since that era? Or at least as indulgent (and greedy) enough to release redundant triple LPs like Yessongs and Welcome Back My Friends....?

Among the many talking heads, Robert Wyatt ("We thought we were a pop band. We were always trying to make normal records; they just didn't come out like that."), Wakeman (who amusingly calls prog the porn of the music industry), and ex-Yes/ex-King Crimson drummer Bill Bruford emerge as the wittiest.

Musing on the advent of punk, Bruford notes "a permanent tension in rock music between the three chords and the truth merchants - you know, 4/4 and three chords - and the other people like me who say, 'What if we added a fourth chord and put it in 5/4?' There are always people like me messing up what these people think is pop music."

Prog fanatics may grouse about a few omissions. Aside from The Nice, here's no hint of other coeval rock-classical hybrids such as Deep Purple's Concerto for Group and Orchestra; Pink Floyd remains but a spectral presence; and a couple of other cult groups, namely Henry Cow and Gentle Giant, merit more than a mention. Also, the post-1980 era was more than a coda for the 70s proggers to go pop; anyone remember Marillion or Spock's Beard?

An oddly chosen and almost incongruous snippet of "Shhh/Peaceful" from the Miles Davis LP In a Silent Way underscores the closing montage and hints at a concurrently expanding interest in form and electronics in jazz, but that's another documentary altogether...