Floyd, who revealed in July that he was battling against bowel cancer, died at his partner’s home in Dorset last night, his ghost writer James Steen said.
The 65-year-old’s booze-fuelled television shows made him a household name and he wrote more than 20 books.
His latest autobiography, Stirred But Not Shaken, in which he describes his battles with the bottle, is to be published next month.
Co-author Mr Steen said: “Writing the book was amazing, it was like a dream come true.
“For an autobiography, you have to be introspective and he found that difficult to start with, but yesterday when I spoke to him he was a really happy man. He was very excited about it. The experience for him was therapeutic.”
Floyd was difficult to work with at times but Mr Steen said this was partly due to his illness.
“He had cancer and no one knew it. There were times when it was difficult because he was already in a lot of pain and he was taking painkillers and drinking on top of that.
“But he wasn’t like that all the time, he had curbed the drinking.
“He was a very generous man, he was very kind and extremely sharp and witty. He knew how to eat well and he was able to convey that. He was a genius at what he did.”
Yesterday, fellow chefs paid tribute.
Antony Worrall Thompson said: “I worked with him a lot and I was a good friend of his. I think all of us modern TV chefs owe a living to him. He kind of spawned us all.
“He turned cookery shows into entertainment. He lived life to the full and didn’t care what people thought about him. He was a good British gent with a very posh accent but he crossed all parts of society — no one thought he was a prat.
“He made cooking approachable and fun. He made us relax about food — until Keith came along, people were very uptight about eating out and he helped us to chill out about it.”
Channel 4 star Jamie Oliver said Floyd was the premier TV chef and a huge influence on other kitchen gurus.
He said today: “Keith was not just one of the best, he was the best television chef. An incredible man who lived life to the full and an inspiration to me and to so many others.”
Gordon Ramsay said: “Keith Floyd was a true original. A natural performer and a superb cook. He broke new ground with his programmes and his contribution to television cookery was immense.”
Nigel Slater said the flamboyant cook’s broadcasts were a “joy to watch”.
He said: “Keith Floyd was responsible for helping to break down many of the barriers of cooking. His free-form, somewhat casual style at the stove made cooking look easy, and encouraged people to have a go.
Raymond Blanc said Floyd would be sadly missed.
Speaking from his Oxfordshire restaurant, he said: “In his own characteristic way, Floyd was a genius.
“He demystified food and made it a popular craft. He was the first chef to reform TV completely. He truly was a charming and generous man. I will miss him.”
Celebrity chef Marco Pierre White paid tribute to a “beautiful man”.
He told BBC Radio 4’s Today programme: “Keith, in my opinion, was an exceptional human being. He had great qualities.
“If you look at TV chefs today, they don’t have his magic. It’s a very, very, very sad day for my industry and secondly for a nation.”
“The thing which is very sad is a little piece of Britain today died which will never be replaced. He was a beautiful man.”
A documentary on Floyd was screened on Channel 4 last night, and former manager John Miles said the chef looked “quite bad” during the programme.
He said: “I was with him at the very beginning. He was closing his restaurant because of money troubles and he asked if I would manage him and make him some money. So I spent the next 10 years making a lot of money for him and then he blew it all.
“We had a lot of good times and quite a few differences of opinion. He was quite a character. He was a very kind guy. He did have a monstrous side but I was lucky to know the very kind side. He changed my hair colour in the time that I managed him.”
Janice Hadlow, controller of BBC2, said: “From the very beginning of his long and successful relationship with BBC2, Keith Floyd pioneered a new kind of cookery programme driven by his exuberant passion for good food, good wine and a good time.”
South Western Ambulance Service confirmed medics were called to an address in Bridport at 8.43pm yesterday to a report of a man in a life-threatening condition.
A Dorset police spokeswoman said Floyd’s death had been reported to the coroner.
Floyd’s final TV appearance was broadcast on Channel 4 on Monday night.
In the show, Keith Meets Keith, the actor Keith Allen searched for his hero, Floyd, finally meeting him in rural France.
Today Allen said: “I’m so glad that I managed to meet one of my heroes before he unfortunately died.
“I’m in receipt of an email from Keith which he sent after he viewed the programme last week, in which he praised the show — he loved it. In typical Keith fashion he observed ‘the only weakness in the show is a certain K Floyd’.”