Following a later incident in the Tourist Trophy at Dundrod, in which Macklin crashed his Austin-Healey 100S avoiding an accident in which Jim Mayers and William T. Smith were killed, Macklin retired from motor sport at the urging of his then girlfriend.
Tras un incidente posterior no Tourist Trophy en Dundrod, no que Macklin estrelouse co seu Austin-Healey 100S, evitando un accidente no que Jim Mayers e William T. Smith morreron, Macklin retirouse do deporte automobilístico a instancias da súa noiva.