Twelve-year-old Georgina Horlick's illness was diagnosed when she was two. Mrs Horlick spent much of the past six months at her daughter's bedside and she, with her husband and other members of the family, were with Georgina when she died on Friday afternoon.
The City fund manager, 37, dubbed "superwoman" because of her business success while simultaneously being a mother of five, said in a written statement: "Georgie died from a lung infection six months after a bone- marrow transplant, which was part of her treatment for leukaemia.
"She fought bravely through nine years of treatment. However she had a relapse last December and underwent the bone-marrow transplant in May, which had left her particularly susceptible to illness."
Dr Alison Leiper, an associate specialist in paediatric oncology at Great Ormond Street Hospital, London, said: "Georgie Horlick was a remarkable little girl who bore her illness with a courage and determination of one much older than her short 12 years.
"We at the hospital all felt privileged to know her and enjoyed her mischievous sense of humour and witty intelligence, which was frequently evident even during the times when she felt unwell.
"She was a loving and generous child who spent much of the last few weeks of her illness making gifts to sell at her school Christmas fair to raise money for the hospital. She will be sadly missed."
A family friend of the Horlicks said: "Clearly they are extremely upset at this time and they would like to be left alone with their family and friends."
Mrs Horlick hit the headlines last year when she was suspended from her pounds 1m job at the merchant bank Deutsche Morgan Grenfell for alleged disloyalty. She flew to the company's headquarters in Germany with newspaper photographers in tow, as part of her campaign to get her job back. In January, she launched the UK arm of Societe Generale Asset Management, which invests large sums for institutions such as pension funds.
Despite her success, Mrs Horlick said she would have happily given it all up to save her daughter. "I asked her if she would like me to stay at home, but she said, `No mummy, I know you will be bored,' " she told the Daily Mail last year.
Mrs Horlick campaigned for the Leukaemia Research Fund and last year she dedicated the proceeds of her book Can You Have It All? to Great Ormond Street Hospital.
There are about 1,200 cases of childhood leukaemia diagnosed every year. In 1973, only 30 per cent of children would have survived the illness - now the figure is between 70 and 75 per cent.Reuse content