The plaintiff was required to serve its expert report in April 2011 and the experts were ordered to meet and prepare a joint expert report by late June 2011. On the third day of the trial the plaintiff delivered an expert report. The expert opinion in the report concerned the manner in which a coach screw was fixed to the pole, which was considered to be material to the issues.
The Court considered that the principles in the Aon case ((2009) 239 CLR 175) concerning late applications to amend applied equally to expert reports (at ). Citing Ultra Thoroughbred Racing v Those Certain Underwriters & Ors (Ruling)  VSC 370, the Court set out the principles to be applied when considering a late application to amend (at ):
In Aon, the High Court said:
An application for leave to amend a pleading should not be approached on the basis that a party is entitled to raise an arguable claim, subject to payment of costs by way of compensation. There is no such entitlement. All matters relevant to the exercise of the power to permit amendment should be weighed. The fact of substantial delay and wasted costs, the concerns of case management, will assume importance on an application for leave to amend. Statements in JL Holdings which suggest only a limited application for case management do not rest upon a principle which has been carefully worked out in a significant succession of cases...
A party has the right to bring proceedings. Parties have choices as to what claims are to be made and how they are to be framed. But limits will be placed upon their ability to effect changes to their pleadings, particularly if litigation is advanced. That is why, in seeking the just resolution of the dispute, reference is made to the parties having a sufficient opportunity to identify the issues they seek to agitate.
In the past it has been left largely to the parties to prepare for trial and to seek the court’s assistance as required. Those times are long gone. The allocation of power, between litigants and the courts arises from tradition and from principle and policy. It is recognised by the courts that the resolution of disputes serves the public as a whole, not merely the parties to the proceedings. (emphasis omitted)
Aon demonstrates that there are a number of factors relevant to an application such as this. For instance:
(a) whether there will be a substantial delay caused by the amendment;
(b) the extent of any wasted costs;
(c) whether there is an irreparable element of unfair prejudice caused by the amendment;
(d) concerns of case management arising from the stage in the proceeding when the amendment is sought;
(e) whether the grant of the amendment will lessen public confidence in the judicial system; and
(f) whether a satisfactory explanation has been given for seeking the amendment at the stage when it is sought.
It is, however, to be remembered that the primary question still remains: what do the interests of justice dictate? Aon reminds us that the prism through which these interests are viewed is wider than just that of the moving party.
The Court refused the plaintiff's application to rely on the expert report for the following reasons:
- The plaintiff claimed that the expert report was provided late because the defendant provided its reports late. However the defendant's reports did not, or at least scarcely did, refer to the issue of the coach screw discussed in the plaintiff's expert report (at  and ).
- The issue of the coach screw was a live issue from the commencement of the proceeding and the plaintiff knew of this issue since September 2009 (at  to ).
- The receipt of the expert report could derail the expert conclave scheduled in the trial, and the plaintiff's expert did not participate in the joint report (at ).
The Court did find that no demonstrable prejudice was demonstrated by the defendant, however the Court said that this was not a determinative factor (at ).
This ruling demonstrates the universal nature of the principles in Aon. It also is a warning that parties need to ensure their expert reports and statements under Order 44 are filed and served in accordance with the Court Orders, otherwise the party whose report is not accepted by the Court will not be able to rely on that expert evidence (see Rules 44.03(1) and 44.05 of the Supreme Court (General Civil Procedure) Rules 2005)).