Key Points:

Peter Maxwell Stewart lived a life most people would envy.

He is the son of Canterbury industrialist Sir Robertson Stewart, and his family's multimillion-dollar fortune, made in plastics and electrics, gave him a springboard for business success that ensured a luxurious life of beautiful homes, expensive yachts and cars, and mixing in high society circles.

His family made $97 million from the sale of its company, PDL, but Stewart had become a successful deer farmer on an expansive Canterbury property, ran a luxury yacht charter company in Picton, indulged his love for motor racing and married model Pieter Stewart, who would become the founder of Fashion Week and mother of his four children.

Yet for all he had, it seems Stewart had a sordid weakness that would become his downfall.

The 62-year-old is facing the distinct lack of luxury of a prison cell after a jury this month found him guilty of raping, sodomising and violating a girl from the age of 8.

The acts occurred between 30 and 40 years ago, in various places around the South Island while he was married to Pieter, who continues to stand by her husband.

Mrs Stewart also knew the victim and said she never saw any sign of abuse, but prosecutor Phil Shamy said she never picked it up "because she was never looking for it".

Stewart was driven by lust and an urge to control, and took risks by abusing his victim even when others were around, Mr Shamy said.

His victim had been manipulated to the stage where she was infatuated with Stewart, but there was a "significant power imbalance when you have a man that was 14 years older".

The abuse convictions are a devastating blow for the Stewart family, which has had their reputation damaged by the convictions and intense publicity that has followed.

Dressed in an expensive suit, Stewart shook and looked dazed as the guilty verdicts were delivered by the jury in the High Court in Christchurch.

At least one of several family members in the public gallery broke down and cried.

His defence that his victim was a fantasist, a liar and a blackmailer had failed.

Stewart has maintained his innocence, admitting only to consensual sex with the victim once, when she was 17, and is likely to appeal against the convictions.

In his evidence, Stewart described the incident in which he had sex with the victim on board his boat after a fishing trip.

He described her "horsing about in a brief white bikini" and "making overtures to me".

"At that point I made probably the biggest mistake of my life and we had sex. I knew this was bad news and it never happened again."

When his victim first made allegations of abuse about 27 years later that filtered back to his wife, Stewart was forced to admit to his single indiscretion.

"She called me a disgusting bastard. It was the first time I had told anyone about it. We had been married for 35 years and it was a horrendous situation."

Sensing he would lose his marriage, children and the businesses he and his wife had created together, he left the family home.

He later returned and his marriage remained intact, but worse was to come for him.

After negotiation between lawyers for his victim and his own family, Stewart's stepmother, Lady Adrienne Stewart, offered the victim a home in a top Christchurch suburb.

But the offer was turned down and instead the allegations went to court.

Stewart is free on bail to spend time with his family over Christmas, but faces the likelihood of jail when he is sentenced in February.