After at least four deaths and a year of protests about top-up payments, Alan Johnson, the health secretary, is expected to declare that National Health Service rules allowed them all along.

In an announcement which is due to be made to parliament at the beginning of November, Johnson is expected to “clarify” government policy, claiming that patients are already permitted to pay for private drugs while continuing to receive NHS care. He will state that the problem arose because of a misinterpretation by some NHS hospitals.

Although it represents a victory for the campaign, led by The Sunday Times, it will be heartbreaking for the families of cancer patients who died after their NHS care was withdrawn because they topped up their treatment.

This weekend one family made public an emotional letter telling of the anguish and outrage caused by the NHS decision to withdraw care.

The letter, written by Linda Linton, a mother of three who died from bowel cancer at the age of 57, tells how she asked to be discharged from hospital because she feared her rising treatment bills.

Linton had her routine treatment withdrawn by Maidstone and Tunbridge Wells NHS Trust because she paid privately for the drug cetuxi-mab which was recommended by her NHS consultant.

Linton, from Sittingbourne, Kent, wrote: “I wanted to go home because I was worried about the mounting costs of my treatment, room and food.

I was told that if I discharged myself I was at risk of multiple organ failure.”

Linton, who wrote the letter four months before her death in October 2006, explained how the scandal was draining her energy: “It is six in the morning and I should be resting and trying to recover from my ordeal, but I am too upset and angry about what has happened to me . . .

“I thought that I could pay for this drug and resume treatment but this is not the case. I have been forced to become a private patient and pay for everything. Could you please inform me who is responsible for the decision to force me out of the NHS?”

Linton was one of dozens of cancer patients who have been told by the NHS that if they top up their care with a private drug recommended by their consultant they will forfeit the rest of their health service care.

John Baron, constituency MP of Linda O’Boyle, who died in March aged 64 after her NHS care was withdrawn because she paid for the cetuxi-mab drug, said of Johnson’s expected announcement: “That will clearly be a U-turn by the government. This position will not fool anybody.”

Patients who have been denied NHS care because they bought private drugs are suing for the treatment which has been withdrawn.

Although dozens of NHS trusts have told cancer patients that they cannot buy private drugs while simultaneously receiving NHS care, The Sunday Times revealed in July that numerous others have been allowing top-ups.

Johnson is expected to announce a solution that will avoid creating a two-tier NHS, with patients in the same ward receiving different standards of care according to their ability to pay.

The University Hospitals Birmingham NHS Foundation Trust treats patients who supplement their NHS care by paying private hospitals or companies for extra drugs. Professor Nick James, a consultant oncologist at the trust, expects Johnson to endorse this approach nationally.

“I don’t think they are going to like the spectacle of patients in adjacent beds getting different treatments and one of them getting better at the end of it. They will try to partition it off so that it is invisible to the NHS patients,” James said.

The Department of Health said: “We know there is variation in how individual trusts are applying the current guidance and that is why the secretary of state asked Professor Mike Richards, national clinical director for cancer, to lead a review.”

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