(1) This rule applies if—(a) the plaintiff makes an offer that is not accepted by the defendant; and(b) the plaintiff obtains an order no less favourable than the offer; and(c) the court is satisfied that the plaintiff was at all material times willing and able to carry out what was proposed in the offer.
(2) Unless the defendant shows another order for costs is appropriate in the circumstances, the court must order the defendant to pay the plaintiff’s costs—(a) calculated on the standard basis, up to and including the day of service of the offer; and(b) calculated on the indemnity basis, after the day of service of the offer.