In September 1973 Harrison applied for a job with Don Nichols's Advanced Vehicle Systems company in Northampton. This organization built the Shadow F1 cars with substantial backing from Universal Oil Products. The UOP Shadow team had had a good first season with drivers George Follmer and Jackie Oliver and was expanding. Harrison was hired by team manager Alan Rees to be a van driver.For the new season Follmer was replaced by Peter Revson and Oliver concentrated on CanAm sportscars and was replaced by Frenchman Jean-Pierre Jarier. Unfortunately, in March, Revson was killed in a testing crash in South Africa. He was replaced by Brian Redman and later by Tom Pryce. While this was all going on Harrison had been given the job of setting up a spares department at Shadow.Jarier and Pryce failed to win in 1974 and 1975 and UOP - losing patience - pulled out at the start of 1976, leaving the team to struggle through the season. Oliver saved the day, finding the necessary backing to keep the team going but then disaster struck again when Pryce was killed in South Africa. The team regrouped and by midsummer had the talented driver pairing of Alan Jones and Riccardo Patrese. In the rain in Austria Jones gave Shadow its first victory. It was not enough to stop the team splitting at the end of the year, however, with sponsor Franco Ambrosio, Rees, Oliver, engineers Dave Wass and Tony Southgate and Patrese combining to form a new team called Arrows at nearby Milton Keynes. One of the lesser-known defectors was Harrison.The new team opened its doors in November 1977 and by January had revealed the Arrows FA1/1. This was later banned by the High Court in London because it was considered to be a copy of the Shadow DN9 but Arrows quickly built a replacement called the A1.Harrison coordinated all Arrows transportation, worked as a tire man at races in the years that followed and by the early 1980s had moved into coordinating the team's travel and freight arrangements. In 1988 he became assistant team manager to Rees and later to John Wickham - who was made team manager after Footwork took control of the team. Finally, in February 1995 Wickham left the team and Harrison was appointed team manager.Tom Walkinshaw's takeover of Arrows in 1997 led to his departure after 18 years with the team. He was briefly involved with the disastrous Mastercard Lola F1 team in 1998 but disappeared from F1 after that.