“The [FSS]’s DNA Interpretation model takes into account the possibility of stochastic variation, therefore in SGM+ and LCN analysis one would make an assessment of the quality of the electrophoretogram and reproducibility of the results. In my opinion stochastic variations are not an important issue in this case as aliquots from the same DNA extract have been run 6 times, the results were highly reproducible and showed no significant stochastic variation. In my opinion, these observations give a more reliable indicator of whether stochastic variation has occurred rather than the Quant value.”
“The learned trial judge wrongly ruled that the DNA evidence from [the FSS expert] was sufficiently reliable to be admitted in evidence.”
“At these very low levels of DNA, the dangers presented by the possibility of stochastic effects, including allelic drop-out, drop-in and stutter are very real and must be fully appreciated, but they may often be addressed by repeating the process a number of times, as Professor Caddy recognised. There will of course be occasions where profiles generated from less than 200pg are wholly and obviously unreliable. We anticipate that the Crown would never seek to adduce such profiles in evidence. If it put forward such a profile, then the unreliability would be pointed out in the report of the defence expert and, if not accepted by the Crown’s expert in the exchange that must take place under Part 34 of the Criminal Procedure Rules, the judge would have to consider the dispute; if they were unreliable, he would exclude them. There will be other occasions where the probative value of the profiles is more debatable. In such cases the evidence may properly be adduced and it must then be addressed and its weight established by adversarial forensic techniques. But we do not accept that these are reasons for ruling out LTDNA evidence altogether. In our judgment, the science of LTDNA is sufficiently well established to pass the ordinary tests of reliability and relevance and it would be wrong wholly to deprive the justice system of the benefits to be gained from the new techniques and advances which it embodies, in cases where there is clear evidence (adduced in the manner discussed) that the profiles are sufficiently reliable.”
“(1) Where it appears to a judge of the Crown Court that an indictment reveals a case of such complexity, a case of such seriousness or a case whose trial is likely to be of such length, that substantial benefits are likely to accrue from a hearing – (a) before the time when the jury are sworn, and (b) for any of the purposes mentioned in subsection (2), he may order that such a hearing (in this Part referred to as a preparatory hearing) shall be held. (2) The purposes are those of – (a) identifying issues which are likely to be material to the determinations and findings which are likely to be required during the trial, (b) if there is to be a jury, assisting their comprehension of those issues and expediting the proceedings before them, ………. (d) assisting the judge’s management of the trial, (e) considering questions as to the severance or joinder of charges.”
“Given the co-extensive powers of case management outside the preparatory hearing regime, courts ought to be very cautious about directing a preparatory hearing under section 29 CPIA or section 7 CJA 1987; in particular, the desire of one party to test a ruling by interlocutory appeal is not a good enough reason for doing so, unless the point is one of the few which is genuinely suitable for that procedure (see para 21 above) and there is a real prospect of such appeal being both capable of resolution in the absence of evidence and avoiding significant wastage of time at the trial.”
“We should add that this case illustrates the complications introduced where the preparatory hearing regime is invoked. It is emphatically not the case that most heavy fraud or similar cases will nowadays call for a preparatory hearing. Virtually the only reason for directing such a hearing nowadays is if the judge is going to have to give a ruling which ought to be the subject of an interlocutory appeal. Such rulings are few and far between and do not extend to most rulings of law. An interlocutory appeal can be a most beneficial process in a few, very limited, circumstances. If a discrete point of law arises, its resolution in this court, can if necessary be accomplished within a very short time-frame and this can avoid the risk of many weeks of wasted trial time. On the other hand, many points of law decided in the Crown Court turn out to be fact sensitive and to appear differently, or for that matter, to go away, by the time the evidence has been heard……”
“…if…the judge has addressed the issues of complexity and length, in the context of the declared purposes of any preparatory hearing, and decided to proceed on the basis that the potential advantages outweigh the disadvantages, this Court will be reluctant to set aside what under the section, and, on the facts of the individual case, is a matter for judicial assessment and decision by the trial judge.”
“There will be cases which obviously fit within the relevant statutory criteria and purposes. There will be others where these issues are not as clear-cut. The judge may, for example, decide to start the investigation on the basis that he has in mind to make a pre-trial ruling under Part IV [of the CPIA], and then, during the course of the argument, decide that on analysis the relevant criteria are established. As a matter of jurisdiction, we see no reason why, having heard from both sides and exercising his discretion, the judge may not conclude that a preparatory hearing should be ordered and start then and there.”
“Once a preparatory hearing has validly been ordered, the power to make a ruling under section 9 is thus on any view exercisable – whatever the direct or dominant object of the application or ruling – whenever the judge reasonably considers that it would also serve a useful trial purpose within one of the heads in section 7(1) to make such a ruling”