truthful in his testimony. I have concerns regarding Dr. Bail’s
independence and his methodology; I do not have any concerns
about his veracity.
(2) What should the trial judge have done in this
 Under the White Burgess framework, and in most other
leading cases on the admissibility of expert evidence, the issue of
admissibility is decided at the time the evidence is proffered and
the expert witness’ qualification is requested by a party. To the
extent that this is possible, it should be the norm: R. v. J. (J.-L.),
 2 S.C.R. 600,  S.C.J. No. 52, 2000 SCC 51, at para. 28.
 In the present case, however, the trial judge appears to
have assumed that, once Dr. Bail was qualified as an expert, his
gatekeeper role was at an end. The trial judge erred in law in
reaching that conclusion.
 A trial judge in a civil jury case qualifying an expert has
a difficult task. She must make a decision based on an expert
report that will, in most cases, never be seen by the jury. While
the report provides a roadmap of the anticipated testimony and
specific limits may be placed on certain areas of testimony, the
trial judge obviously cannot predict with certainty the nature or
content of the expert’s testimony.
 Where, as here, the expert’s eventual testimony removes
any doubt about her independence, the trial judge must not act
as if she were functus. The trial judge must continue to exercise
her gatekeeper function. After all, the concerns about the impact
of a non-independent expert witness on the jury have not been
eliminated. To the contrary, they have come to fruition. At that
stage, when the trial judge recognizes the acute risk to trial
fairness, she must take action.
 Charron J.A. made this point in K. (A.), writing as follows,
at para. 73:
In some cases it may be possible to rule on the admissibility of the proposed
evidence on the basis of counsel’s submissions alone. However it may at
times prove necessary to hold a voir dire in order to properly consider all
relevant factors. Where the trial is before a jury and the question of admis-
sibility cannot be clearly determined in a summary fashion, it may indeed
be prudent to scrutinize the evidence during the course of a voir dire before
admitting it. While in some cases the ruling can be made early in the pro-
ceedings, in other cases, it may be only later in the trial that the value of the
proposed evidence can be properly assessed. For example, in this case, it was
only after the main Crown witnesses had testified and the defence strategy
became apparent that the determination of the admissibility of the expert
evidence could properly be made.
(Emphasis added and footnote omitted)