 Mainwaring was cited as a major intellectual inspiration by the radical British labour leader Tom Mann.In his 1923 memoirs, Mann credited Mainwaring with having been "one of the very first to understand the significance of the revolutionary movement, and the first, as far as my knowledge goes, to appreciate industrial action as distinct from parliamentary action".Mainwaring was the namesake of a nephew whom he adopted, Sam Mainwaring Jr., himself an important radical activist in the international labour movement.