 In 1934, Gill contributed art to an exhibition mounted by the left-wing Artists' International Association, and defended the exhibition against accusations in "The Catholic Herald" that its art was "anti-Christian".Gill was adamantly opposed to fascism, and was one of the few Catholics in Britain to openly support the Spanish Republicans.Gill became a pacifist and helped set up the Catholic peace organisation Pax with E. I. Watkin and Donald Attwater.