The Court of Session is the highest civil court in Scotland.

What this means

When a judge makes a decision in a civil court it can be appealed in a civil court that has more authority, who can decide the judge’s decision was wrong. But then their decision can also be appealed in a civil court with more authority than that.

The highest civil court is the one with the most authority of all. Once they make a decision, it can only be appealed to the UK Supreme Court, and only in some circumstances.