Hotson (P), when aged 13, fell from a tree and suffered an acute traumatic fracture of the left femoral epiphysis. He was not correctly treated for five days and suffered avascular necrosis, involving disability of the hip joint and the virtual certainty of osteoarthritis. The Health Authority (D) admitted negligence. The trial judge assessed that there was a 75 percent the chance that avascular necrosis would have developed from the fall anyway, and awarded damages based on the loss of a 25 percent chance of full recovery. The damages attributable were 46,000 pounds, and this was discounted by 75 percent to yield an award of 11,500 pounds. D appealed.