"An application to amend will be refused if it is clear that the proposed amendment has no real prospect of success. The test to be applied is the same as that for summary judgment underCPR Part 24 ."
"Drawing these authorities together, the relevant principles can be stated simply as follows: (a) whether to allow an amendment is a matter for the discretion of the court. In exercising that discretion, the overriding objective is of the greatest importance. Applications always involve the court striking a balance between injustice to the applicant if the amendment is refused, and injustice to the opposing party and other litigants in general, if the amendment is permitted; (b) where a very late application to amend is made the correct approach is not that the amendments ought, in general, to be allowed so that the real dispute between the parties can be adjudicated upon. Rather, a heavy burden lies on a party seeking a very late amendment to show the strength of the new case and why justice to him, his opponent and other court users requires him to be able to pursue it. The risk to a trial date may mean that the lateness of the application to amend will of itself cause the balance to be loaded heavily against the grant of permission; (c) a very late amendment is one made when the trial date has been fixed and where permitting the amendments would cause the trial date to be lost. Parties and the court have a legitimate expectation that trial fixtures will be kept; (d) lateness is not an absolute, but a relative concept. It depends on a review of the nature of the proposed amendment, the quality of the explanation for its timing, and a fair appreciation of the consequences in terms of work wasted and consequential work to be done; (e) gone are the days when it was sufficient for the amending party to argue that no prejudice had been suffered, save as to costs. In the modern era it is more readily recognised that the payment of costs may not be adequate compensation; (f) it is incumbent on a party seeking the indulgence of the court to be allowed to raise a late claim to provide a good explanation for the delay; (g) a much stricter view is taken nowadays of non-compliance with the Civil Procedure Rules and directions of the court. The achievement of justice means something different now. Parties can no longer expect indulgence if they fail to comply with their procedural obligations because those obligations not only serve the purpose of ensuring that they conduct the litigation proportionately in order to ensure their own costs are kept within proportionate bounds but also the wider public interest of ensuring that other litigants can obtain justice efficiently and proportionately, and that the courts enable them to do so."
"... particularly if it will/may well cause disruption to the trial timetable. Principle (d) [in Mrs Justice Carr's decision] is important in considering 'lateness'."
"Even if the first proposed set of amendments does not threaten the trial in and of itself it is incumbent upon a party, here the claimant, in line with Mrs Justice Carr's principle (b) above, to show that a new case sought to be advanced has sufficient strength so as to justify its introduction as late as it is being sought to be introduced and to show 'why justice to him or to his opponent and other court users requires that the claimant be allowed to pursue it'."