In another 2014 interview in "Doctor Who Magazine", Sherwin recalled that after submitting his scripts for "The Invasion" to Bryant, which included UNIT, Sherwin, who was also working freelance as a script editor, was told by Bryant to introduce his UNIT idea earlier, as it could "take some of the weight off shoulders" of actor Patrick Troughton, who played the Doctor. Speaking in an interview on the 2011 special-edition DVD of "Spearhead from Space", Sherwin claimed that he had created UNIT because he wanted to give some "considerable support" to the Doctor, "so that [Troughton didn't have so many damn lines to learn each week".