View source for Collateral Fact Rule

{{LevelZero}}{{HeaderCredibility}}
==General Principles==
A collateral fact is a "fact not directly connected" or not relevant to "the issue in dispute"<ref>
{{CanLIIRx|MC|fqk75|2012 ONSC 882 (CanLII)}}{{perONSC|Thornburn J}} citing Black's law Dictionary
</ref>
The collateral fact rule prohibits the admission of any evidence that would tend to contradict any previously admitted collateral evidence. Any extrinsic contradictory evidence that brings a witness's credibility into question may not be considered where the contradictory evidence not relevant to an issue at trial.<ref>
{{CanLIIRP|Prebtani|219zr|2008 ONCA 735 (CanLII)|240 CCC (3d) 237}}{{perONCA|Rosenberg JA}}<br>
{{CanLIIRP|Cargill|gcrsh|1950 CanLII 382 (MB CA)|[1913] 2 KB 271 (C.C.A.)}}<br> 
{{CanLIIR-N|Hrechuk| (1950), 10 CR 132}}{{atp|135}}<br> 
{{CanLIIRP|Rafael|g165h|1972 CanLII 640 (ON CA)| OR 238 (CA)}}{{perONCA-H|Arnup JA}}{{atp|330}}<br>
{{CanLIIRP|Latour|1z71v|1976 CanLII 145 (SCC)|[1978] 1 SCR 361}}{{perSCC|De Grandpre J}}{{atp|367}}<br>
{{CanLIIRP|Cassibo|g1c0b|1982 CanLII 1953 (ON CA)| OR (2d) 288}}{{perONCA-H|Martin JA}}{{atp|506}}<br>
{{supra1|MC}}<br>
{{CanLIIRP|Sanderson|h4639|2017 ONCA 470 (CanLII)|349 CCC (3d) 129}}{{perONCA|Pepall JA}}{{atL|h4639|47}}
</ref> 
When a witness speaks to a fact, the veracity of the testimony can only be brought into question where it is sufficiently material to a trial issue. Otherwise, it will fall up against the collateral fact rule that prohibits the calling of contradictory evidence on immaterial facts. Thus, testimony on collateral issues is conclusive. This rule has been codified in certain legislation including s. 10 and 11 of the CEA.

Collateral evidence is also characterized as evidence which derives its relevance only from the fact that it is admitted for the purpose of contradicting other evidence and nothing else.<ref>
{{CanLIIRx|JH|g71t7|2014 NLCA 25 (CanLII)}}{{perNLCA|Harrington and Hoegg JJA}}{{atL|g71t7|33}}<br>
</ref>

A foundational test for collateral fact is whether the evidence contradicting the statement of the witness could be validly led as evidence on its own.<ref> 
{{UKCase|AG v Hitchcock| (1847), 154 ER 38}} at 42<br>
{{CanLIIRP|R(D)|1fr85|1996 CanLII 207 (SCC)|[1996] 2 SCR 291}}{{perSCC| Major J}}<br>
</ref>
Thus, statements to evidence that is not directly connected to a material fact cannot be contradicted.<ref>
{{CanLIIRP|Aalders|1fs39|1993 CanLII 99 (SCC)|82 CCC (3d) 215}}{{perSCC|Cory J}}</ref> 

The rule equally applies in cases that turn on credibility.<ref>
{{CanLIIRP|McIntosh|1f9wt|1999 CanLII 1403 (ON CA)|141 CCC (3d) 97}}{{perONCA|Weiler JA}}{{atL|1f9wt|86}}<br>
{{CanLIIRx|Van Leeuwen|fplzq|2012 ONSC 132 (CanLII)}}{{perONSC|Durno J}}<br>
{{supra1|Prebtani}}<br>
</ref>

; Purpose
The purpose behind the rule is to "avoid confusion", "proliferation of issues", "wasting time" and the introduction of evidence of negligible use.<Ref>
{{supra1|Sanderson}}{{atL|h4639|47}} citing Watt's Manual of Criminal Evidence
</ref>

; During Cross-examination
The CFR does not limit what is otherwise a valid question on cross-examination.<ref>
{{CanLIIRP|MacIsaac|h03gk|2017 ONCA 172 (CanLII)|347 CCC (3d) 37}}{{perONCA|Trotter JA}}{{AtL|h03gk|58}} ("The collateral fact rule does not curtail what is otherwise proper cross-examination of a witness; it potentially limits the manner in which answers given may be subsequently challenged by extrinsic evidence")
</ref>
It may however limit where the examining party can introduce extrinsic evidence contradicting the witness.<Ref>
{{ibid1|MacIsaac}}{{atL|h03gk|58}} ("As is often said, if the questioner asks a question that bears on a collateral issue, he or she is “stuck” with the answer, in the sense of not being permitted to lead extrinsic evidence to contradict it. However, this does not prevent proper questions from being put in the first place")<Br>
</ref>
{{reflist|2}}

==Exceptions to the Rule==
Exceptions exists for certain evidence going to credibility:<ref>
{{CanLIIRP|R(D)|1fr85|1996 CanLII 207 (SCC)|[1996] 2 SCR 291}}{{perSCC|Major J}}<br>
{{CanLIIRP|Cassibo|g1c0b|1982 CanLII 1953 (ON CA)| OR (2d) 288 (CA)}}{{perONCA-H|Martin JA}}<br>
{{CanLIIRP|Biddle|1frlj|1995 CanLII 34 (SCC)|[1995] 1 SCR 761}}{{perSCC|Sopinka J}}<br>
</ref>
* existence of material previous statement<ref>
{{CanLIIRPC|Masztalar v Wiens|231ng|1992 CanLII 5953 (BC CA)|2 WWR 706}}{{perBCCA|Cumming JA}}<br>
</ref>
* prior convictions
* honesty or history of lying
* bias or partiality<ref> See R v Lindlau; however, if admitted more evidence cannot be lead</ref>
* motive to fabricate<ref>
{{CanLIIRP|P(G)|5n42|1996 CanLII 420 (ON CA)|112 CCC (3d)}}{{perONCA|Rosenberg JA}}</ref>
* bad reputation
* perception
* memory
* ability to communicate.

Where a witness denies having an animus against the accused at the time of the offence may be contradicted with extrinsic evidence. However, where a witness concedes having an animus against the accused at the time of the offence, they may be cross-examined on an ongoing animus including at the time of trial. <ref>
{{CanLIIRx|Farquharson|1clsk|2002 CanLII 41775 (ON CA)}}{{TheCourtONCA}}
</ref>

A collateral answer to a question does not prohibit otherwise valid cross-examination on this issue.<ref>
{{CanLIIRP|MacIsaac|h03gk|2017 ONCA 172 (CanLII)|347 CCC (3d) 37}}{{perONCA|Trotter JA}}{{atL|h03gk|58}}<br>
{{CanLIIRP|Krause|1ftr1|1986 CanLII 39 (SCC)|[1986] 2 SCR 466}}{{perSCC|McIntyre J}}{{atps|474-475}}<br>
{{CanLIIRP|Khanna|gmxjt|2016 ONCA 39 (CanLII)|127 WCB (2d) 613}}{{TheCourtONCA}}{{atL|gmxjt|9}}<br>
</ref>

; Mental or Physical Disorders
A party may violate the collateral fact rule in presenting medical evidence to establish that by some mental or physical illness, the witness is incapable of giving reliable evidence, whether due to delusion or otherwise.<ref>
{{supra1|MacIsaac}}{{atL|h03gk|59}} - referred to as "Toohey evidence"<br>
</ref>

{{reflist|2}}