This particular gig came less than a week after they recorded the famous Musikladen TV special in Hamburg (two tracks from that show on DVD here). Support was Leo Kottke.
We don't know what they played on this occasion, but there's a setlist from three days later here.
The recording of Exotic Birds and Fruit was to start in about six weeks' time.
Gary Brooker is the only Procoler we can clearly see here. He's talking to Barry Sinclair, who sent BtP the excellent touring schedules a while back. Keith Reid is seated, in the leather jacket: the rest await identification.
Chris Copping and Alan Cartwright are also shown ... no sign in this shot of Messrs Grabham or Reid.
Note the influence of the Home album insert (see here) on Claes Valentin's posture!
In 1973 he was a professional photographer, though the Procol pictures
were not intended for publication at that time. These days he's building windmills.