Re: the above posts. Jeremy felt trapped in the farming way of life: long hours, not sufficient remuneration to support his lavish lifestyle, lack of appreciation and grumbles from Nevill he wouldn't do overtime. I don't think there was any definite plan growing up; surrounded by the children of the landed gentry at Gresham's he would be pretty low in the social pecking order, nor would he have felt comfortable academically in that stuffy male-dominated environment. He went through the motions, with no real plan or ulterior motive, sensing his father's disappointment at his academic prowess, attempting an escape of sorts with the Little Chef job at Rivenhall End, then working at Sloppy Joe's in Colchester and helping out odd times at the Frog and Beans.
It is difficult to say how the petty crime of drug dealing and stealing money from the caravan park escalated into mass murder. Maybe as he witnessed his mother's breakdown in 1982 and his sister's two breakdowns, followed by Nevill's bout of illness requiring him to relinquish the magistrate's job, it started out with him getting ideas beyond his station. To his mind he was the only one unaffected by malady, though maybe cognitive distortions came into play when claiming Nicholas and Daniel would grow up disturbed, the reality being that he may have been jealous that Sheila had provided issue where he himself had failed.
As for Julie, she was swept along in a maelstrom of emotion I doubt most males could comprehend, in love as she was and not wanting to confront the reality of what he was confiding in her. So sad that she was on teaching practice at a difficult time for the education profession (one recalls Margaret Thatcher being refused an honorary degree at Oxford in January 1985 for the alleged damage she had caused) as her mind struggled with competing demands for her attention, and she tragically made the wrong choice.