The court may at any time correct an accidental slip or omission in any certificate or order issued by the court and may vary any certificate, order or judgment in order to make the meaning and intention of the court clear: see CPR 40.12 (often known as the “slip rule”) and the Part 40 Practice Direction supplementing it. Although it is mainly used to correct typographical or arithmetical mistakes, the slip rule can also be used to correct other more substantial errors and omissions in expressing the intention of the court.