See the signature?
A promo photo from the No Little Boy period.
This was also used for the cover of the songbook John Martyn For Guitar Tab.
This scan was taken from the Cooltide program. It must be a promotional picture in use by Permanent Records but they never credited it to my knowledge.
This photo with Alan Thomson on bass was found on Twitter. Geezer Butler confirmed that is was taken at the Sub Club, 28 December 1988.
Robert Laugier: "I saw John twice in October 1987, the first time in the Hammersmith Odeon [09 Oct], and the second one, two days later, in the Town & Country Club of Kentish Town.
For the first concert, John arrived wearing a raincoat which he kept only during the first song, and then took off.
Two days later, he arrived wearing with the same raincoat... but kept it on all concert long!
Each time John was lowering a hand, sweat was flowing down the sleeves like a cascade."