The right to full disclosure is just one component of the right to make full answer and defence. It does not follow that solely because the appellant’s right to full disclosure was breached, his/her Charter right to make full answer and defence was also compromised.
Obtaining a New Trial on the Basis of Non-Disclosure
To obtain a new trial on the basis of non-disclosure, the appellant must establish, on a balance of probabilities, that there is a reasonable possibility that the non-disclosure affected either
(1) the outcome of the trial, or
(2) the overall fairness of the trial process.
STEP ONE Establish Breach of the Right to Disclosure
Where evidence proposed for admission on appeal has to do with information that was not disclosed prior to trial, an appellant must first establish that the undisclosed information meets the Stinchcombe standard and thus amounts to a breach of the appellant’s constitutional right to disclosure.
R. v. Dixon, 1998 CanLII 805 (SCC),  1 S.C.R. 244, at para. 22; R. v. Taillefer; R. v. Duguay, 2003 SCC 70 (CanLII),  3 S.C.R. 307, at para. 61; T.S., 2012 ONCA 289 (CanLII, at para. 123.
The appellant must next establish, on a balance of probabilities, that the disclosure failure impaired the appellant’s right to make full answer and defence.
Dixon, at para. 33; T.S., at para. 124.
STEP TWO Establish Breach of the Right to Full Answer and Defence
Here the court inquires whether there is a reasonable possibility that the undisclosed evidence, when considered in the context of the trial as a whole, could have impacted on the verdict. A new trial should be ordered where it is so established.
Taillefer, at para. 82; Dixon, at para. 36.
Here the court inquires whether there is a reasonable possibility that the undisclosed evidence would have affected the defence’s opportunity to pursue meaningful lines of inquiry with witnesses or gather additional evidence that would have been available but for the non-disclosure.
Dixon, at paras. 34,36; R. v. M.G.T., 2017 ONCA 736 (CanLII), at para. 152; R. v. Iles, 2008 SCC 57 (CanLII), at para. 65; Taillefer, at paras. 83-84.
· Where an undisclosed statement of a witness could reasonably have been used to impeach the credibility of a prosecution witness;
· Where the prosecution fails to disclose to the defence that there is a witness who could have led to the timely discovery of other witnesses who were useful to the defence.
An important factor in considering the impact of a disclosure failure on the overall fairness of the trial process is the diligence of defence counsel in pursuing disclosure from the Crown. A lack of due diligence in pursuing disclosure is a significant factor in determining whether the Crown’s non-disclosure affected the overall fairness of the trial process:
Dixon, at para. 37; R. v. M.G.T., at para. 15.
Where defence counsel knew or ought to have known of a disclosure failure or deficiency on the basis of other disclosures, yet remained passive as a result of a tactical decision or lack of due diligence, it is difficult to accede to a submission that the disclosure default affected the overall fairness of the trial.
Dixon, at para. 38; R. v. McAnespie, 1993 CanLII 50 (SCC),  4 S.C.R. 501, at pp. 502-503.