"... it is said, as an expert witness, someone to whom, the Crown says, you can listen to and have regard to in the nature of the opinions that he gave. Well, courts are able to hear evidence from experts, as we say, giving opinion evidence. That evidence is given on a variety of bases and you have heard that mentioned in this particular case and you are able to give effective weight to it if you so decide to do. However in relation to the evidence of opinion given by expert witnesses it is a matter for you to determine, having regard to the total evidence, the weight which you are going to give to the evidence of the expert or the evidence of opinion. I am not suggesting one way or another how you should find in relation to the evidence given by the police officer or the accused, who gave some evidence as to the matters which had been commented on by way of opinion from the police officer. All I am saying to you is that you are able to rely upon opinion evidence, but you must look at it and you must make your own decision about whether in the light of all the circumstances you are going to accept and rely upon the opinion on certain matters, one, more, all of them, or not. That is a matter entirely for you."