"(1) To encourage the saving of private costs and the avoidance of the inherent risks delays and uncertainties of litigation by promoting early offers of compromise by defendants which amount to a realistic assessment of the plaintiff's real claim which can be placed before its opponent without risk that its `bottom line' will be revealed to the court; (2) To save the public costs which are unnecessarily incurred in litigation which events demonstrate to have been unnecessary, having regard to an earlier (and, as found, reasonable offer of compromise made by a plaintiff to a defendant;) and (3) to indemnify the plaintiff who has made the offer of compromise, later found to have been reasonable, against the costs thereafter incurred. This is deemed appropriate because, from the time of the rejection or deemed rejection the compromised offer, notionally the real cause and occasion of the litigation is the attitude adopted by the defendant who has rejected the compromise. In such circumstances that party should ordinarily bear the costs of litigation."