"This probative force is derived, if at all, from
the circumstance that the facts testified to by
the several witnesses bear to each other such a
striking similarity that they must, when judged
by experience and common sense, either all be
true, or have arisen from a cause common to the
witnesses or from pure coincidence. The jury
may, therefore, properly be asked to judge
whether the right conclusion is that all are
true, so that each story is supported by the
other(s).
I use the words 'a cause common to the
witnesses' to include not only (as in Rex v.
Sims 1946 KB 531) the possibility that the
witnesses may have invented a story in concert
but also the possibility that a similar story
may have arisen by a process of infection from
media of publicity or simply from fashion. In
the sexual field, and in others, this may be a
real possibility: something much more than mere
similarity and absence of proved conspiracy is
needed if this evidence is to be allowed. This is
well illustrated by Reg. v. Kilbourne 1973 AC
7 29 where the judge excluded 'intra group'
evidence because of the possibility, as it
appeared to him, of collaboration between boys
who knew each other well. This is, in my
respectful opinion, the right course rather than
to admit the evidence unless a case of
collaboration or concoction is made out.
If this test is to be applied fairly, much
depends in the first place upon the experience
and common sense of the judge."
(Original emphasis.)