The Duchess – the pet name that Jimmy Savile used for his mother Agnes Savile – died in 1972.
But what was her relationship with her youngest son really like, and was she suspicious of his behaviour (as depicted in the earlier episodes of BBC One's drama The Reckoning)?
Raised as part of a Roman Catholic family, Jimmy was one of seven siblings (he had four sisters and two brothers) and was the last to be born. Jimmy's father was Vincent Joseph Marie Savile, a bookmaker's clerk, but he didn't talk too much about his dad.
Jimmy Savile is said to have claimed not to have had much of a childhood, without children his own age to play with. He also described himself as his mother's 'not again child', having been born just before she had turned 40; Jimmy had not been planned or wanted.
Related: The Reckoning review: Is the BBC's Jimmy Savile drama justified?
"I grew up with adults, which meant I didn't have anything to say," Savile told journalist Dan Davies while interviewing for his book. "I finished up with big ears, listening to everything, and big eyes, watching everything, and a brain that wondered why grown-ups did what they did."
Savile was said to have spent his adult life trying to win his mother's acceptance and approval, after a lack of affection as a youngster. After his father died, he took an even keener interest in his relationship with her.
Savile bought his mother a flat on Scarborough's Esplanade, which he decorated to his own taste, where he routinely stayed with her until she died and continued to reside afterwards.
Jimmy Savile and his mother attended Church together on Sundays and would also go on holiday together, including a trip to Rome to visit the Vatican.
Agnes Savile attended Buckingham Palace with her son to collect his OBE in 1971.
Not too long after this, Agnes died, aged 85, and Jimmy was said to have been devastated. It's been widely reported that he spent days with her body after she passed.
"To me, they were good times," Savile reflected years later. "Once upon a time I had to share her with other people. We had marvellous times. But when she was dead she was all mine, for me."
In an interview with the Sunday People (via the Mirror) he gave some further insight into the dynamic of the relationship with the Duchess.
"My mother never got round to being proud," he told the publication. "If anyone said, 'What is Jimmy like?' she would say, 'I don't know what he's up to, but he's up to something'.
"She never trusted me as she thought I was going to get nicked and end up in the pokey."
Although it's impossible to know whether or not she was suspicious of his criminal behaviour, it's been said that she was untrusting of his success.
During Louis Theroux's 2000 documentary When Louis Met... Jimmy Savile, Savile took Louis to the Scarborough apartment he'd shared with his mother the Duchess. He told the documentary maker that they "never" argued.
"Pale golden hair she had," Savile described his mother, "perfectly natural, and was the envy of many ladies right the way until the time she pegged it."
He took Louis around the Duchess's old bedroom, showing him her wardrobe which still had his mother's clothes in. "My cleaner takes them out and gets them freshened up about once a year," Savile told him. "These make better souvenirs than photographs," he added.
Louis observed that, 30 years after her death, his mother was still the most important person in his life.
After Jimmy Savile's own death in 2011, news came to light of sexual abuse allegations against him with multiple victims coming forward. It's now estimated that he violated more than 400 people over a time span of more than 50 years.
In 2016 Louis Theroux did a follow-up documentary to speak to some of Savile's victims (one of whom told Louis he'd been "hoodwinked" by Savile in his earlier 2000 film), in an attempt to explore how he had gotten away with his crimes for so long. A BBC drama, The Reckoning, is now aiming to do the same thing.
The Reckoning airs on BBC One and the full series will also be available on BBC iPlayer.
TV Editor, Digital Spy Laura has been watching television for over 30 years and professionally writing about entertainment for almost 10 of those. Previously at LOOK and now heading up the TV desk at the UK's biggest TV and movies site Digital Spy, Laura has helped steer conversations around some of the most popular shows on the box. Laura has appeared on Channel 5 News and radio to talk viewing habits and TV recommendations. As well as putting her nerd-level Buffy knowledge to good use during an IRL meet with Sarah Michelle Gellar, Laura also once had afternoon tea with One Direction, has sat around the fire pit of the Love Island villa, spoken to Sir David Attenborough about the world's oceans and even interviewed Rylan from inside the Big Brother house (housemate status, forever pending).
