He represented the Lions on their tours to South Africa in 1974, New Zealand in 1977 and South Africa in 1980. It was during the game against the Junior All Blacks on the 1977 tour that the famous 'Mudman' image of Cotton, waiting for the ball at a lineout while caked head-to-toe in mud, was taken. Captured by Colorsport's Colin Elsey, it became one of the most iconic images of rugby union.