What should be done if a mat is not on the centre line when starting an end?

When starting an end in bowls, it is essential that the mat is positioned correctly on the centre line of the rink. This alignment ensures fairness and uniformity in play, as it maintains the intended dimensions of the playing area for both teams. If the mat is not on the centre line, realigning it to the centre line is necessary to uphold the rules of the game and confirm that each player will have an equal opportunity to play.

Positioning the mat correctly allows the bowlers to throw their bowls from a standardized starting point, which is crucial for competitive integrity. Failing to realign could lead to confusion and potential disputes during the game, as one team's playing conditions may differ from the other's.

Options such as starting the end without adjustments or agreeing to a new position could compromise the game's fairness and structure, while placing a marker does not actually resolve the issue of correctly aligning the mat. Therefore, realigning the mat to the centre line is the proper action to ensure a fair and regulated game.