A non-runner is a selection that's named but doesn't take part in an event. A typical example is a horse that's scheduled to run in a race, but doesn't.
In most circumstances, if your selection is a non-runner, your bet will be void (and your stake returned). If the selection is part of a multiple, the bet will become the next accumulative bet down, e.g. a treble becomes a double etc.
However if your bet's an Ante-Post bet (see rules for Ante-Post betting) it will be classed as a losing bet.
For a list of today's Horse Racing non-runners, please click here.