As the news broke, tributes poured in from friends in the worlds of fashion and the arts. A spokesman for the Princess of Wales said: "She is devastated, like all those who loved him."
The photographer David Bailey, who with Donovan was a key figure of the Sixties, said: "He was the Orson Welles of photography - and my best friend."
Donovan, who was 60, was found hanging in his new, unfinished studios in Ealing, west London. He had been taking steroids as a result of a skin infection, and had been depressed as a result, a family source said last night. His wife, Diana, 54 yesterday, said: "I am completely devastated. We had been married for 26 years. He was the most wonderful man."
Without Donovan and his close friend Bailey, it is hard to imagine modern British photography. He began when photographers did little but snap family portraits or weddings; today, they can be highly-paid artists in their own right, admired and respected for their talent in bringing the best out of people. Then they were second-class citizens, invited to the party but not allowed to mingle with the guests. Now, at the best parties, it is the likes of Donovan and Bailey who are photographed.
This twist was not lost on Donovan. He was always amazed that he could stay at the most expensive hotels, eat at the most expensive restaurants with members of the Royal Family and former prime ministers - and then be asked to take their picture. The variety always surprised him as well. One minute, as he once pointed out, he could be snapping Harold Macmillan; the next, a fisherman.
The sense of wonder stayed with him; from the heady Sixties, when he made his name with portraits of Twiggy, Jean Shrimpton and Julie Christie, to one of his last projects, a set of rock stars for GQ magazine.
Everyone who knew him yesterday spoke of his warmth and vitality, his energy and, above all, his humour. Lord Snowdon said: "He was tremendously kind to people - you will not find one person in the industry with an unkind word to say about him. He was incredibly funny, but he was never funny at other people's expense."
The only son of a lorry driver, he was brought up in the Mile End Road during the war. At 11 he left his secondary modern to attend a course in blockmaking at Fleet Street's London School of Engraving and Lithography.
For a while it looked as though lithography would be his chosen career. "My Uncle Joe was a lithographer and he was the top bloke in the family ... good money, you know," he said.
But once he joined the photographic department of a Fleet Street blockmaker at 15, the buzz of creating pictures, of watching them develop from a blank piece of paper, began to possess him. According to Snowdon, he insisted on developing his prints himself and loved being in the dark- room.
The moribund state of British fashion was crying out for his energy and his talent for looking at things in a different light and trying new angles, first with John French, then a top photographer, whose studio he joined, then on his own, for the likes of Vogue and Town magazine.
He photographed beautiful women but also made men look striking. "It is not so long ago that the only way you photographed a man was on a shooting stick in Regents Park. So I thought, right, we'll get on to this. We'll go to the gas works."
The money was good but his love was pictures. He insisted:"I was always much more interested in doing the thing than being the thing. I was much more interested in photography than being a photographer."
For a while he switched tack, moving into directing television commercials. A feature film - Yellow Dog - followed in 1972, and he also produced plays for CBS, documentaries for LWT and pop promotions.
But photography remained his first love. He recently worked for Vogue, Harpers & Queen, Elle, Marie Claire as well as GQ.
Outside photography, he developed an all-consuming interest in judo, rising to black belt. A large man, he was a formidable opponent, even in later life. Judo was a let-out, a release and contrast from glamour photography. "In judo there is no shield, no Armani overcoat to hide behind. There is immediate physical contact. You learn about yourself when you are faced with an enormous ginger-haired bloke with every other tooth missing, salivating at the thought of pushing you straight through the mat," he said in 1992.
That intensity - he gave up drinking at 25 and was a devout non-smoker - may explain his death.
A friend said last week, he sounded very low. He was talking about the art and the craft not being noticed any more. "It did not matter if you photographed a truck in Arizona or something you really cared about - you were judged in the same way," he told the friend.
He was depressed that after raising his art, it had become devalued, that the effort required to produce a memorable picture was being forgotten and all that mattered was the subject and their name.
Donovan would have liked the tribute from Snowdon yesterday: "He was one of the great British photographers and on a par with Irving Penn in America."
The irony of such an accolade from a Lord, a former husband of a royal and another Sixties figure, would not have been lost on the boy from the East End.
Bailey on Donovan
"He was special, he was unique. Only Britain can produce people who are so lovably eccentric.
"Donovan changed things, he made photography human. His personality was so strong, you only had to look at a picture to know it was a Donovan.
"He was a photographer's photographer. All his work was so powerful I could not choose one outstanding image. It was all brilliant. He was an Orson Welles of photography, in every way, in stature and in his presence. But on top of that, there was his humour, which was on a par with Peter Ustinov. He was erudite and very droll, always to the point.
"He had a kind of cockney zen. He used to say `the whole point of life is continuous change'. That was the way he lived his own life. He was crazy about judo which was part of that zen. He had become quite a good painter, too, with great Japanese-style strokes. He used a paintbrush 2ft wide rather than a small pen.
"He cut through the class thing completely. In the early days he had a bad accent. It could be really tough.
"He never let anyone down, he was one of those guys you would want next to you when the enemy come marching towards you. I last saw him three weeks ago at his birthday party. He wanted to bring in the Gurkhas playing bagpipes but could not arrange it in time. That was the kind of thing he'd do.
"On Sundays we drove around the East End just looking at things. We would go to the art shop in Stepney and buy paints. I can't tell you how great he was, not only as a photographer, but as everything, as a piece of life. He was my oldest friend. Now it's like the f---ing moon not being there any more."