[2] Colledge's guideless ascent of a number of difficult routes in the Alps resulted in an invite to join Eric Shipton's Cho Oyu expedition in 1952.
[5] In 1969, in a two-week holiday from his job at Courtaulds in Derby, he made three difficult ascents that brought him to the attention of the British climbing community.
[6][7] Partnering Dan Boon, Colledge made an ascents of the Pear Buttress on Mont Blanc and the Walker Spur on the Grandes Jorasses.
[8] Colledge then made the third British ascent of the 1938 route on the north face of the Eiger.
[9][10] Colledge went on to make many early British ascents of difficult Alpine routes with his friend and climbing partner Dennis Davis.