Third party proceedings can be an efficient, and cost-effective way of adding parties and any related claims arising from the same set of facts. Rule 29.02 provides the time constraints for when third party claims must be issued: within ten days after the delivery of a statement of defence, within ten days after the plaintiff delivers a reply in the main action, or at any time after this, either with the plaintiff’s consent or with leave of the court. Leave must be granted by the court according to the Rule, unless the plaintiff would be prejudiced thereby, which the court has interpreted as needing to be “more than a mere inconvenience”. Examples of when the court has found prejudice to the plaintiff and has disallowed the commencement of third party proceedings include when examinations for discovery have long been completed or when trial for the matter is imminently approaching and the addition of a third party claim would cause an inordinate delay to same.
Problems arise because oftentimes in insurance law, information as to potential third party claims only comes to light once certain evidence is provided, either through documentary production or through examinations for discovery, and by this time, there may be a limitation period issue. Section 18 of the Limitations Act, 2002 marginally addresses this problem, providing that for claims of contribution and indemnity, whether arising from a tort or otherwise, the limitation period is presumed to begin to run from the date that defendant is sued. This buys a little more time for a third party claim to be commenced.
The question remains of whether the discoverability principles in section 5(2) of the Limitations Act, 2002 apply to the running of such a limitation period for third party claims of contribution and indemnity; essentially, whether consideration is given to the point at which a defendant discovered or ought to have discovered sufficient facts to make it possible to bring its third party claim. Although there is some conflicting case law on this point, the most recent word from the Court of Appeal in 2015 on this point in Miaskowski v Persaud is that the start date for the limitation period in section 18 is a presumed start date, so that discoverability provisions do apply. If the defendant can show reasonable due diligence in determining a potential claim and can show that it was only discovered subsequent to the date he was served with the claim, that presumption will be rebutted and the limitation period will be determined to begin on that day of discovery. It is the defendant who bears the onus of proving he used reasonable due diligence and took steps to discover the potential claim and the identity of the third party prior to the expiry of the limitation period. A defendant cannot sit idly by, having knowledge of a potential third party claim, and waiting on the commencement of same.
A good discussion of what this required due diligence looks like in the context of an automobile insurance claim can be found in the Justice Gordon’s decision in White v Mannen, where the defendant submitted that the examinations for discovery and accompanying expert opinions were necessary to have first in order to discover the cause of action against the third party. The court emphasized that the test for discoverability requires that the party have knowledge, actual or constructive, of “material” or “sufficient” facts necessary in order to commence a claim only, rather than enough facts or evidence to be in a position to “prove” the claim. Essentially, all the defendant must know for a third party claim to be deemed as “discovered” is that there is a potential third party who may have been involved in some way in the injuries claimed, and the identity of this third party; details as to potential liability are not required to be known at this point.
As discussed in White v Mannen , in some cases, this will require an expert opinion in order to ascertain the material facts, as was the case in Zurba v Lakeridge Health Corp. It was only after the defendant received an expert medical opinion that identified the initial care provided by the doctor at the hospital as a possible cause of the plaintiff’s injuries, that discovery of this third party claim was established. The limitation period for commencement of the third party claim thus only began to run upon receipt of this expert report.
Similar principles apply to examinations for discovery; an examination for discovery may or may not be necessary to be completed prior to knowledge of a third party claim. For example, in Bentley v Ontario (Ministry of Transportation), the defendant asserted that it only discovered its third party claim against the municipality after the examination for discovery which disclosed a new or different version of the facts, as to the iciness of the bridge and whether or not there were signs warning of bridge icing. However, the court rejected this argument, finding that no new or different information about the presence or absence of signs warning about bridge icing were actually disclosed at the examination for discovery, as the witness merely provided she could not recall either way, so that the defendant failed to rebut the presumption that the limitation period began to run on the date he was served. The defendant ought to have already known of the potential liability of the municipality in the injury claimed; no new information as to the nature of the damages implicating the third party was obtained at the discovery. Thus, in order for the court to find it necessary for an examination for discovery to be held prior to the third party claim being discovered, there must be material facts discovered for the first time in that discovery, as relating to the nature of the injury itself.
The standard used for the question of whether due diligence was satisfied in discovering the potential third party claim is that of a “reasonably prudent person in pursuing the facts”. The principle of “better to be safe than sorry” definitely applies in this instance to avoid a claim being statute-barred, impressing upon defendants the need, where possible, to be speedy with bringing any third party claims against individuals potentially involved in the fact situation, rather than waiting for concrete evidence of proof against such persons to come to light.
 Rule 29.02(1) of the Rules of Civil Procedure, R.R.O. 1990, Reg. 194, as amended.
 Siket v Milczek (1993), 23 C.P.C. (3d) 204 at para 6 (Ont. Gen. Div.)
 Ibid at para 6.
 Section 18 of Limitations Act, 2002, S.O. 2002, c. 24, Sched. B; Placzek v Green, 2009 ONCA 83 at para 24.
 Hughes v Dyck, 2016 ONSC 901 at para 23.
 Miaskowski (Litigation Guardian of) v Persaud, 2015 ONCA 758 at para 27.
 White v Mannen, 2011 ONSC 1058 at para 16.
 Ibid at para 26.
 Ibid at paras 27, 28.
 Zurba v Lakeridge Health Corporation, 2010 ONSC 318 at para 66.
 Supra note 8 at para 28.
 Bentley v Ontario (Ministry of Transportation) (2009), 182 A.C.W.S. (3d) 958 (ONSC) at para 15.
 Ibid at para 19.
 Ibid at para 15.
 Castronovo v Sunnybrook & Women’s College Health Sciences Centre (2008), 163 A.C.W.S. (3d) 225 (ONSC) at para 13, affirmed 2008 ONCA 655.