The British rugby league system is based on a five-tier structure administered by the Rugby Football League. There is no system of automatic promotion and relegation between all five tiers although teams have moved between them in the past. Since the 2015 season, the act of promotion and relegation has been re-introduced in the form of a new format including end-of-season play-offs across a variety of different leagues, however automatic promotion and relegation between the varying leagues (such as the professional leagues and the NCL) still does not exist.