"(1) A Part 36 offer must be in writing. (2) A Part 36 offer may relate to the whole claim or to part of it or to any issue that arises in it. (3) A Part 36 offer must (a) state whether it relates to the whole of the claim or to part of it or to an issue that arises in it and if so to which part or issue; (b) state whether it takes into account any counterclaim; and (c) if it is expressed not to be inclusive of interest, give the details relating to interest set out in rule 36.22(2). .... (6) A Part 36 offer made not less than 21 days before the start of the trial must (a) be expressed to remain open for acceptance for 21 days from the date it is made; and (b) provide that after 21 days the offeree may only accept it if (i) the parties agree the liability for costs; or (ii) the court gives permission."
"Where a claimant's Part 36 offer is accepted without needing the permission of the court the claimant will be entitled to his costs of the proceedings up to the date upon which the defendant serves notice of acceptance."
" (1) This rule applies where at trial (a) a defendant is held liable for more; or (b) the judgment against a defendant is more advantageous to the claimant, than the proposals contained in a claimant's Part 36 offer. (2) The court may order interest on the whole or part of any sum of money (excluding interest) awarded to the claimant at a rate not exceeding 10% above base rate for some or all of the period starting with the latest date on which the defendant could have accepted the offer without needing the permission of the court. (3) The court may also order that the claimant is entitled to (a) his costs on the indemnity basis from the latest date when the defendant could have accepted the offer without needing the permission of the court; and (b) interest on those costs at a rate not exceeding 10% above base rate. (4) Where this rule applies, the court will make the orders referred to in paragraphs (2) and (3) unless it considers it unjust to do so. .... (5) In considering whether it would be unjust to make the orders referred to in (2) and (3) above, the court will take into account all the circumstances of the case including (a) the terms of any Part 36 offer; (b) the stage in the proceedings when any Part 36 offer .... was made; (c) the information available to the parties at the time when the Part 36 offer .... was made; and (d) the conduct of the parties with regard to the giving or refusing to give information for the purposes of enabling the offer or payment into court to be made or evaluated. (6) Where the court awards interest under this rule and also awards interest on the same sum and for the same period under any other power, the total rate of interest may not exceed 10% above base rate."