I think that you’re missing the point here. No matter how Luke behaved HE WAS A CHILD and therefore should not have been subjected to the bullying tactics the police employed.
From Luke Mitchell-v-Her Majesty’s Advocate 2008.
‘ Having considered the transcript of the interview, we are driven to the conclusion that some of the questions put by the interviewing police officer can only be described as outrageous. At times the nature of the questioning was such that the questioner did not seem to be seriously interested in a response from the appellant but rather endeavouring to break him down into giving some hoped-for confession by his overbearing and hostile interrogation. Such conduct, particularly where the interviewee was a 15 year old youth, can only be deplored.’
Always wise not to take excerpts out of context, because the next bit says
“However, the issue for determination in this appeal is whether the answers to the particular questions, which alone the Crown sought to introduce in evidence, were elicited in such circumstances that the trial judge was bound to hold that they were inadmissible. Having considered the response of the appellant throughout and in detail each of the passages in dispute, we are satisfied that the trial judge was entitled to take the course which he did. Moreover, having regard to the context of the questions and responses, many of which related to matters already otherwise properly in evidence, we are not persuaded that on this ground a miscarriage of justice can be said to have resulted”.
So, despite “deploring” Mitchell’s questioning, no miscarriage of justice was said to have taken place, that’s the salient point.