Warthur Much as a generation of neo-prog acts would do over a decade later, King Crimson honed their version of prog in part through a well-received series of appearances at the Marquee. Recorded the day after the band's historic supporting performance at the Rolling Stones' Hyde Park concert, this archival release finds them more able to stretch out and improvise than they were in Hyde Park, because when you're a new band who've been given a golden spot by the Stones you don't repay that favour by making them late for their set.

The recording quality is shaky - somewhat shakier than the Hyde Park recording, and since the Marquee was an indoor venue with its own in-house sound system rather than an outdoor festival I feel less generous about the recording quality here than I am about the Hyde Park stuff, but at the same time the additional improvisation and some intriguing sonic bits - like Drop In, an old Giles, Giles and Fripp number given a heavier spin here and which is recognisably an early version of what would later, with new Peter Sinfield lyrics, become The Letters from Islands. It's a testament to the creativity of this version of the band that bits of music from this era would still be drawn on to fill out the running time four albums into their career.

Three and a half stars, round up to four stars if you are a big fan of the 1969 lineup of the band. If you have deep pockets and want the sound quality to be as good as it can be, this is in the Complete 1969 box set and has been given as much care and repair as can be expected. (Trees, a bonus track from a Fairfield Halls concert appended to previous releases on this, is relocated to the BBC Sessions disc on that set.)