The girl, from Cambridgeshire and known only as "B" after a High Court ruling that she should not be identified, has already had two courses of chemotherapy and a bone marrow transplant. Her family had asked for more chemotherapy and another transplant, but cancer specialists last month gave her less than a 10 per cent chance of survival even with the treatments, and refused them.
The girl's case has been widely seen as a refusal of possibly life-saving treatment because of financial considerations.
The donation yesterday followed nationwide publicity after her parents won a High Court ruling on Friday that Cambridge Health Authority must provide treatment, only to see the ruling overturned six hours later in the Court of Appeal.
Michael Sinclair, the family's solicitor, said that the money was already in a bank account waiting to be used.
Two national tabloid newspapers had offered to pay for the treatment, launching appeals in yesterday's editions. Several others are believed to have offered the family substantial sums in return for exclusive rights to their story. The child's father had been unwilling to do this, wishing to spare his daughter the glare of public scrutiny.
Mohamed al-Fayed, the chairman of Harrods, had also offered to help, but last night a Harrods spokesman said he was not the anonymous donor.
Cambridge and Huntingdon Health Commission, purchasers for the health authority, said in a statement yesterday that all the doctors to which the girl had been referred thought the treatment would be inappropriate. "The advice from doctors treating her was that this aggressive treatment would be detrimental to her quality of life. The chances of survival were very slight," the commission said.
Virginia Bottomley, the Secretary of Sstate for Health, also insisted that the decision not to treat the girl further had been taken on medical grounds alone. "I think to try to blame resources in this question is really misleading," she said, adding that if the doctors had decided the treatment was appropriate, the health authority had made clear the resources would have been provided.
"If my child was treated by Addenbrookes and I had had a second opinion from the Marsden [hospitals] - two outstanding world-class centres of excellence - I think I would personally be deeply influenced by those leading clinicians," Mrs Bottomley said. "But I think all of us understand the parents in this case feeling that they wanted to explore all the options."
The case has raised in acute form the thorny question of priority setting in the NHS, where limited funding meets potentially limitless demand. Hugh Bayley, Labour MP for York, called on the Commons Health Select Committee to reopen its inquiry into "rationing" in the health service in the light of Child B's case. Mr Bayley, a member of the committee, said it should investigate to what extent budget pressures led to the health authority's decision.
The committee said in a report six weeks ago that some treatments, such as fertility treatments, were excluded from the NHS because they were considered only marginally beneficial.
It concluded there should be "no absolute exclusion of service from NHS provision".
Mr Sinclair said the girl's family was "delighted" that the money had been raised: "I have received a letter from another firm of solicitors that they have the money in their account. The family has decided to accept the offer," he said. He would give no details about the donor but confirmed the amount was £75,000.
Despite the donation the girl's family is still hoping to get the Appeal Court's decision overturned. "We are investigating whether we can take the case to the House of Lords or more possibly to the European Court of Human Rights," Mr Sinclair said. "The family hopes that the publicity . . . can be used to raise funds for leukaemia research or other suitable charities."
A spokeswoman for the Cambridge and Huntingdon Health Commission, speaking for the health authority, said: "We are pleased for the family that the treatment will now go ahead." NHS speak, page 3 Leading article, page 26Reuse content