The Clydesdale Scottish Premier League as it is now known, formerly the Royal Bank of Scotland Scottish Premier league came into existence in 1998 and originally consisted of 10 teams this was increased to 12 a couple of years later. The small number of teams in the Scottish Premier League means that if each team only played each other twice, as is normal in England, then the football season would be very short, so the Scottish Premier League authorities have come up with a unique solution which does have an effect on the odds quoted by betting companies.
Based on a teams previous performance in the Scottish Premier League, teams are given a seeding, this is an indication of where that team is expected to finish in the Scottish Premier League at the end of the football season. The fixture list is then set up, such that each team plays the others 3 times, after they have played the initial 33 fixtures the Scottish Premier League is Split into a top 6 and a bottom 6 and the teams then play a further 5 games before the final league positions are decided. Using the seeding system to decide the fixture list is an attempt to ensure that at the end of the season each team has played each fixture 4 times, twice at home and twice away. The
system isn't perfect though and sometimes a team could play another one 3 times away and only once at home. This can have an effect on the odds quoted for particular fixtures.
Ever since it's inauguration, the Scottish Premier League has only been won by either Celtic or Glasgow Rangers, the “Old Firm” derbys being the most hotly contested fixtures of the season. Currently Celtic hold bragging rights having won the league more often than Rangers.
Under normal circumstances the team finishing last in the Scottish Premier League is relegated to the Scottish First Division however if the first division winners ground does not meet Scottish Premier League criteria then no relegation or promotion takes place. This situation has caused all sorts of problems in the past and again it's potential effect on the betting community is obvious.

