Colin Simpson was a wing/full-back who first impressed as a strapping runner for Ipswich School in the Rosslyn Park Schools Sevens tournaments of the early 1960s. After joining the Army from school, he made his debut in the Inter-Services tournament against the RAF at Twickenham in April 1963 whilst a cadet at Sandhurst.

He scored the only try of the match, the Army winning 8-6 to take the Services Championship title. The first post-war cadet to play for the Army in the Services Triangular Tournament, he was described in one report as standing 6 ft 6½ ins and weighing 14st … and those were the statistics that appeared against his name in the match programme when he appeared on the wing as one of the Barbarians' uncapped players against Wilson Whineray's All Blacks at Cardiff in February 1964.

Later the same year (while still at Sandhurst) he turned out in the Baa-Baas' side that played a special floodlit match against Cardiff in October. His late penalty made victory certain (12-8) for the touring side and an invitation to turn out for the Harlequins club came soon after.

He left his mark on several of the club's games leading up to Christmas. He scored two tries playing on the wing at Cheltenham (October 31st), landed a touchline conversion in the 17-0 win against Oxford University (November 21st) and crossed for a try in the 13-11 win against Cardiff (December 12th). He also kicked a couple of penalty goals playing for the Combined Services against the French Armed Forces at Twickenham in late December.

Meanwhile he had attracted the attention of the England selectors and played on the wing for the Colours (the junior side) in the first trial at Weston-super-Mare (losing 5-6), for the Probables (losing 13-16) at Fylde, and for The Rest, scoring a late try, in the Final trial at Twickenham on January 2nd, 1965 (the match ending drawn, 9-9).

He was named a few days later to play left-wing in the England side that faced Wales at Cardiff. All four of England's threequarters in that match were new caps but Simpson, whose measurements the programme had now shrunk to a more believable 6 ft 1½ ins, was dropped after a 14-3 defeat. His place on the left wing went to Peter Cook for the Irish and French matches that season and was filled (famously) by Andy Hancock against Scotland in England's last match of the season.