This Practice Note considers making amendments to statements of case (amending pleadings, amending particulars of claim, amending the claim form, amending the defence, amending the reply, etc) under CPR 17. It considers when the court’s permission is required to amend a statement of case. It also considers the grounds on which permission may be granted or refused with reference to the key factors that the court will take into account, such as the overriding objective in CPR 1.1, the need for real prospects of success (the same test as in summary judgment applications), the timing of the application, the need to plead in accordance with the Civil Procedure Rules (CPR), whether the amendment is an abuse of process and the relevance of illegality. This Practice Note explains when you will need the court’s permission to amend a statement of case (pleading) under CPR 17 and describes the process of applying for permission. This Practice Note should be read in conjunction with the following Practice Notes: • Amending a statement of case—introduction