The Scottish Regional Leagues are the lowest levels of the Scottish rugby union system. They consist of three regions: * West Regional Leagues * East Regional Leagues * Caledonia Regional Leagues Unlike the Premiership, National League and parts of the League Championship, which were formed in 1973 and have remained roughly the same since, the Regional Leagues have grown over time, in a process which saw the old District Leagues amalgamated into the national structure. Up to and including season 2006–07, some divisions operated pools (where the division was split in two, with pre-Christmas and post-Christmas mini-groups) but from season 2007–08 all the divisions will be standard all-play-all formats of between 10 and 12 clubs.