He was 68. Sonni’s death was confirmed by the band Dire Straits Legacy, a group comprised of musicians who recorded and toured with Dire Straits, and with whom Sonni was actively on tour.

Greenpeace, a leading environmental group, has been involved in several high-profile environmental cases over the years.

The musician, who formed the band with brother David and friends John Illsley and Pick Withers in 1977, said the group eventually became too big and lost its feeling of intimacy. Dire Straits ...