Federal Court (Full Court): According to the "poisoned well" principle, "it is not unknown for a party’s credibility to have been so weakened in cross-examination that the tribunal of fact may well treat what is proffered as corroborative evidence as of no weight because the well has been poisoned beyond redemption". Does that principle apply to evidence provided by an applicant towards supporting their credibility? In other words, can a decision-maker treat that evidence as "poisoned" too, or is it required to assess that evidence before it forms an opinion on credibility?
The questions to the Federal Court (FCA) were as follows:
Question 1: Does the "poisoned well" principle apply to evidence provided by an applicant towards establishing their credibility? In other words, it is necessarily an error for a decision-maker to find that an applicant's credibility "has been poisoned beyond redemption" without first considering evidence provided by the applicant towards establishing their credibility?
Question 2: Is it necessarily legally unreasonable for a decision-maker to make an adverse credibility finding in circumstances where only 2 inconsistencies were identified "over four hearings and multiple statutory declarations"?
The FCA answered those questions as follows.