Bamber if gulity didn't go into this thinking " I'm definatley going to get away with it" he took a calculated risk,
He lost, and has paid the price heavily.
He is a resilient character with a strong personality and a ready line in conversation, he's managed to go through jail with his facilities in tact. Fighting the case has kept his sanity. Even if gulity and living in fantasy. It's something he can occupy himself with and keep busy.
He's a survivor, and what I mean by that he's felt in his own mind hes never belonged. He was adopted from birth, never had a meaningful close relationship with his adopted family, was shunted to boarding school at a young age.
Had circumstances been different, perhaps he'd be successful person.