A bet is voided when it cannot be fairly settled: the match is postponed or abandoned, a named player doesn't start, a whole-number handicap or totals line lands exactly (a push), or the bookmaker cancels an obvious pricing error (palpable error, 'palp'). Your stake comes back and the bet is recorded as neither a win nor a loss.
Voids matter for record-keeping honesty. In our settled statistics a void books exactly 0 units — it is excluded from win-rate calculations and stakes are not counted as turnover. In accumulators, a voided leg doesn't sink the ticket; the leg is removed and the combined odds are recalculated without it.
Asian handicap −1.0 and the favourite wins 2–1: the one-goal margin lands exactly on the line, the bet pushes, and your £15 stake is simply returned.