Civil Procedure Rules contain two separate provisions relating to agreed extensions of time: CPR 3.8(4) gives a general permission to agree extensions, whereas CPR 15.5 relates specifically to the defence. While this Q&A refers to ‘service’ of the defence, but the requirement in CPR 15.4 is to file the defence within the set period. There is no express time limit for service (CPR 15.6), although an unserved defence risks being struck out. Accordingly, the power to agree an extension of time under CPR 15.5 expressly relates only to filing of the defence, not to its service. Therefore, the short answer to the question is that, regarding service of the defence, there is no time limit to be extended. Where an extension is required for the preparation of the defence so that it can be served and filed,