The two-tier National League comprises 21 sides 11 in the Championship and 10 in Championship One.

The League format as it now exists, with second and third levels below the elite Super League, came into existence in 2003.

When it was introduced, a play-off structure was used to determine the winners of the League and which club would be eligible for promotion to Super League.

That team was replaced by the Super League's bottom club and the same play-off system existed between the second and third tiers.

However, since the introduction of the Super League franchise system in 2009, promotion and relegation between the Championship and Super League have been scrapped and been replaced by a three-year licensing plan.

In 2008 the Salford City Reds and Celtic Crusaders were the top two sides in the National League and since they also met the licensing criteria, they became the last teams to be granted Super League status until 2011.

When Widnes beat Salford 20-18 at the Stobart Stadium in 2008, it was played in front of a crowd of 8,189 which was a record attendance for rugby league at Championship level.