Also, not to forget this doesn't just concern Luke.
There is his mother to consider.
This mother who has stuck by him, fought the cause.
Is there really any choice - for him to admit guilt.
Certainly not whilst his mother is still alive.
The admission of his guilt, in turn could very well,
lead to her incarceration also.
IMO of course.
The same, of course, would be true of any other mother (or partner) who had "stuck by" a son (or partner) who may have been responsible for murder - perhaps by being dishonest or misleading about that son/partner's movements, whereabouts, actions etc in order to avoid suspicion falling on that son/partner.
I'm not, of course, talking about family members who knew nothing about what their loved one had done and therefore told no lies or misled anyone - I'm thinking people like Sonia Sutcliff who, it seems, had no idea what her husband did when he was away. I'm talking specifically about those who knowingly concealed the truth (or their suspicions) in order to protect a loved one.
Before the inevitable howls of protest, I'm not talking about any particular person or family - I'm just making the point that the argument Parky makes here could just as easily apply to others. For nearly every innocent, incarcerated person later released, there was someone else who committed the crime (the exceptions being where there
was no crime), so there is at least the possibility that someone else (or elses) either knew, or had some inkling, and kept schtum.
Sometimes, there are understandable reasons - for example, the children of Fred and Rose West who were too terrified to voice their suspicions. Only when the actions of their parents became known to the authorities were those grown up children safe enough to speak out.
So my point is a relatively simple one - the argument made here by Parky to suggest a reason why Luke may not confess (other than that he has nothing to confess to) could just as easily apply in a number of other circumstances, to other people.