There is no doubt that he was a determined character, admirable in many ways: he rose above the death of one child and the brain-damage of another, and bullied his first wife, Patricia Neal, back to health after a series of strokes. His frustration at the inadequacy of the equipment used to treat his son after an accident in the early Sixties resulted in the invention of the Wade-Dahl-Till valve, which drained the skulls of thousands of children from 1962 until it was superseded. The Dahl Foundation, fed by his royalties, funds neurological and haematological projects to the tune of pounds 400,000 a year.
The down-side of determination, of course, is arrogance. He was a noted womaniser before his marriages. He was always disappointed at not receiving a knighthood, and, according to second wife, Felicity, "was offered an OBE but turned it down. He thought it wasn't enough." The lack of honours might have been connected to his robustly aired views: his 1983 review of God Cried, a book about the Israeli invasion of the Lebanon, in The Literary Review, was considered by many to be the most brazenly anti-Semitic article to be published in a respectable British journal in modern times. One example of a "robustly aired" Dahl view: "Even a stinker like Hitler didn't just pick on them for no reason."
It can't have been easy for Tessa. And she didn't make it easy for herself. Her career as a writer (children's and adults' books and newspaper features) has been overshadowed by her career as darling of the gossip columns. Launching it at 17 with an affair with Peter Sellers, she has rattled from well-publicised relationship to well-publicised marriage break-up almost without pause. Her brief affair with David Hemmings five years ago fell foul of the curse of Hello!: the couple had gone their separate ways within two months of vowing eternal happiness in the magazine. A typical Dahl Junior quote is: "Sometimes I overdosed on falling in love. It was horrible. I can't tell you how horrible it was." Little of the clinical style that characterised the old man has passed itself on to the daughter. In its place is a dramatic talent which, at its worst, can be a little tiresome and at its best can suck blood from the hardest granite.
Public life runs in the blood. Tessa's daughter, Sophie - who first found fame as the little girl in The BFG - is rapidly establishing herself in the firmament of role models: 6ft tall and a statuesque size 14 who refuses to diet, she is one of the hottest models of the moment. Sophie's career started in typically dramatic fashion: Isabella Blow discovered her sobbing on a street corner - "Mummy and I were having a huge row about my prospects. I was screaming, 'I'm not a failure, I will have a proper job' " - and she was immediately signed up by Storm.
Like her forebears, Sophie has little knack for secrecy. Of a German Vogue shoot she says, "It looks like I fit marvellously into the Gianfranco Ferre outfits, when they were all held together with pins." "Fashion should be about making clothes that make all women look beautiful, not making women starve," she says. Extraordinary: the granddaughter of an old-fashioned ladies' man, the daughter of a woman who by her own admission has suffered two bouts of anorexia, and she's all set to be an icon of feminismn