The object was pretty simple, was it not? Compare two items, rock and building slate, said by the Crown to have been recovered by investigating officers in 1997 and 2004 respectively from Coniston, near to in a broad sense where the body of Mrs. Park was found, with stone materials from Mr. Park's former home at Bluestones. The rock we have as our exhibit six in the court numbering, PDB 5/19 engraved upon our minds in a sculptured fashion. The slate is exhibit five. I will probably try and call them the rock and the slate or use the exhibit number to which we have become all familiar.
Well, we first heard from Dr. Pirrie and Professor Pye, who are distinguished geologists. Dr. Pirrie frankly admitted that his work as a forensic scientist was in its early years. I think he said he had worked for 18 months in forensic science, and in fact he was giving evidence in court he told us for the first time. In the previous case in which he thought he might give evidence, his evidence had been accepted by the other side, and so he did not have to turn up in court. He was obviously being challenged about that, but he remained adamant that his methods and approach to the case was adopting geological techniques which were well known and accepted in the academic field. He was also challenged on the basis that he had not adopted the standard forensic science type of comparison about whether things were strong support, weak support, extremely strong support, extremely weak support for X, Y and Z, and he frankly again accepted that he had only heard of that sort of approach after August 2004 when his first report was prepared. Again, however, he was insistent that the methods he had used were tried and tested academically, and of course he used a new machine which he told us all about, but you will have to bear in mind whether his lack of experience is something that makes you think perhaps his evidence is less cogent than Professor Pye's and in other areas where Professor Pye was challenged, but these are matters that are why I said to you earlier on this is trial by jury, not trial by experts, and you assess these extremely distinguished people in the way you assess any other witness.