Gordon Brown has led tributes to the "inspirational" Dame Anita Roddick, who has died from a brain haemorrhage.
The prime minister said the 64-year-old founder of the ethical cosmetics chain Body Shop was "one of the country's true pioneers".
Her husband, Gordon, and daughters Sam and Justine were with her when she died at 1830 BST on Monday at St Richard's Hospital in Chichester, West Sussex.
She had been taken to hospital on Sunday after complaining of a headache.
Dame Anita set up the first Body Shop in Brighton in 1976. She pioneered cruelty-free beauty products and turned them into a highly profitable business.
High street icon
Gordon Brown said of her: "She campaigned for green issues for many years before it became fashionable to do so and inspired millions to the cause by bringing sustainable products to a mass market.
"She will be remembered not only as a great campaigner but also as a great entrepreneur."
Last year the Body Shop was sold to the French company L'Oreal but it is still run independently.
The daughter of Italian immigrants, Dame Anita became one of Britain's most successful businesswomen. She pioneered the ethical sourcing of products at Body Shop and the chain was one of the icons of the High Street in the 1980s.
In the 1990s its fortunes were hit as rivals started making similar products, but the retailer fought back and has more than 2,100 stores in 55 countries.
US animal rights' group Peta (People for the Ethical Treatment of Animals) vice president Dan Mathews said she risked her business to be "the first corporation to announce boldly - in letters a foot high in her store windows - 'against animal tests'."
"Before Body Shop you could only find cruelty-free products in hippie shops - now they are everywhere," he said.
Adrian Bellamy, chairman of The Body Shop International, said: "Anita leaves us with an enduring legacy which will long guide the affairs of The Body Shop.
"Our heartfelt condolences are with the Roddick family at this sad time."
In February Dame Anita announced she had contracted Hepatitis C from a blood transfusion in 1971.
Charles Gore, chief executive of the Hepatitis C Trust, said that after her diagnosis she quickly became a patron of the charity.
"The great thing about Anita was that she took all her causes incredibly seriously but she never took herself seriously, which made her really fun to be with," he said.
She also revealed she was suffering from cirrhosis of the liver after contracting Hepatitis C from blood given during the birth of her youngest daughter.
She said she had unknowingly lived with "this silent killer" for three decades and only found out about it two years ago after a blood test.
"What I can say is that having Hep C means that I live with a sharp sense of my own mortality, which in many ways makes life more vivid and immediate," Dame Anita said.
She told BBC News in July she had been having "some tiny heart attacks", which she put down to "getting in and out of aeroplanes so often".
Clive Stafford Smith, legal director of anti-death penalty organisation Reprieve, said she had just agreed to be its chairwoman.
"We were so happy to have her, she was so full of life, so fantastic," he said.
Emma Colyer from the HIV and Aids charity Body and Soul, which Dame Anita set up, said it was a terribly sad day for society at large.
"Anita carried out campaigns on so many issues and often issues that were not popular by the mass of public," she said.
Amnesty International UK director Kate Allen said Dame Anita's passion for human rights was "immeasurable".
She said: "We have lost a true champion of the oppressed and persecuted."