OPINION EVIDENCE AND EXPERTS NOTES
a. General prohibition on the use of opinion evidence and the exceptions to this
F11.1 General Rule→ W may only give evidence of facts they personally perceived and not
evidence of their opinion, i.e. evidence of inferences drawn from such facts.
TWO EXCEPTIONS:
(a) Non-expertise: statement of opinion on matters not calling for expertise, if made by a
W as a way of conveying relevant facts he personally perceived, is admissible as
evidence of what he perceived.
(b) Experts: statement of opinion on any relevant matter calling for expertise may be made
by a W qualified to give such an expert opinion- the evidence may be accompanied by
animations to illustrate the opinion like graphic 3D reconstructions- but inadmissible in
the absence of sufficiently reliable and precise factual foundations e.g. case tried to
reproduce scene of crime to demonstrate W line of sight in support of expert opinion
that he could not have seen what he claimed – but variables i.e. W location, accused
and objects obstructing W had not been pinpointed accurately (Moore [2017]).
Unless admissibility of the expert opinion evidence is challenged, the judge will admit the
evidence as sufficient safeguards are provided in the pre-trial disclosure rules. If objection to
the admissibility is made, it is for the party offering the evidence to prove its admissibility.
An objection will fail if the W is not an expert. (Foulger [2012]➔ W not an expert
communications data investigator but put telephone data into simple format i.e. charts).
Advocate’s should not ask experts to give an opinion directly on the ‘final’ issue e.g. if the Q
for the jury is whether D caused death by dangerous driving, the advocate without prior leave
should not ask the W ‘is it your opinion that the D caused this death by dangerous driving?’ -
better to ask Qs on components to the driving e.g. the car’s speed by reference to skid marks.
F11.2 Non-expert Opinion Evidence → W may give statement of opinion on a matter not
calling for expertise, as a means of conveying facts perceived by him. So, an identification W
is not required to give a description of the offender, leaving it to the tribunal of fact to decide
whether that description fits the accused, but may express opinion they are the person he
saw. They may give evidence of opinion to identify an object i.e. a picture, handwriting or a
voice he recognises, of a person's age or the general appearance of their state of health, mind
or emotion, the speed of a vehicle, the state of the weather and the passage of time.
BUT: non-expert opinion evidence should not be received on the value of less common
objects or e.g. antiques/art as the valuation calls for expertise. Also, the fitness of the accused
to drive is a matter for expertise, but a non-expert may give evidence of his impression
whether the accused had taken drink, if he describes the facts on the basis of which he formed
that impression and although scientific evidence is not always required to identify drugs, PO
descriptions of a drug must be sufficient to justify the inference it was the drug alleged.
b. Use of Opinion Evidence at trial
a. General prohibition on the use of opinion evidence and the exceptions to this
F11.1 General Rule→ W may only give evidence of facts they personally perceived and not
evidence of their opinion, i.e. evidence of inferences drawn from such facts.
TWO EXCEPTIONS:
(a) Non-expertise: statement of opinion on matters not calling for expertise, if made by a
W as a way of conveying relevant facts he personally perceived, is admissible as
evidence of what he perceived.
(b) Experts: statement of opinion on any relevant matter calling for expertise may be made
by a W qualified to give such an expert opinion- the evidence may be accompanied by
animations to illustrate the opinion like graphic 3D reconstructions- but inadmissible in
the absence of sufficiently reliable and precise factual foundations e.g. case tried to
reproduce scene of crime to demonstrate W line of sight in support of expert opinion
that he could not have seen what he claimed – but variables i.e. W location, accused
and objects obstructing W had not been pinpointed accurately (Moore [2017]).
Unless admissibility of the expert opinion evidence is challenged, the judge will admit the
evidence as sufficient safeguards are provided in the pre-trial disclosure rules. If objection to
the admissibility is made, it is for the party offering the evidence to prove its admissibility.
An objection will fail if the W is not an expert. (Foulger [2012]➔ W not an expert
communications data investigator but put telephone data into simple format i.e. charts).
Advocate’s should not ask experts to give an opinion directly on the ‘final’ issue e.g. if the Q
for the jury is whether D caused death by dangerous driving, the advocate without prior leave
should not ask the W ‘is it your opinion that the D caused this death by dangerous driving?’ -
better to ask Qs on components to the driving e.g. the car’s speed by reference to skid marks.
F11.2 Non-expert Opinion Evidence → W may give statement of opinion on a matter not
calling for expertise, as a means of conveying facts perceived by him. So, an identification W
is not required to give a description of the offender, leaving it to the tribunal of fact to decide
whether that description fits the accused, but may express opinion they are the person he
saw. They may give evidence of opinion to identify an object i.e. a picture, handwriting or a
voice he recognises, of a person's age or the general appearance of their state of health, mind
or emotion, the speed of a vehicle, the state of the weather and the passage of time.
BUT: non-expert opinion evidence should not be received on the value of less common
objects or e.g. antiques/art as the valuation calls for expertise. Also, the fitness of the accused
to drive is a matter for expertise, but a non-expert may give evidence of his impression
whether the accused had taken drink, if he describes the facts on the basis of which he formed
that impression and although scientific evidence is not always required to identify drugs, PO
descriptions of a drug must be sufficient to justify the inference it was the drug alleged.
b. Use of Opinion Evidence at trial
