In a parallel universe, Greg Sutton was an Australian ex-oilman and political prisoner at the Eastchester Scientific Labour Camp carrying out his world's Inferno Project.
Unlike his counterpart of the Third Doctor's universe, who wore a casual cream-coloured safari outfit, the alternate Sutton wore a smart dark brown suit and a navy blue tie with red stripes.
Sutton helped the Third Doctor fight off the Primords which attacked the facility and convinced Petra Williams to help. He openly defied the Brigade Leader in doing so. Sutton helped the Doctor fix his TARDIS console and leave for his universe.
As his world ended, Sutton held Petra, with whom he had formed a relationship. (TV: Inferno)