Patients should be warned about the dangers of chemotherapy after research showed that cancer drugs are killing up to 50 per cent of patients in some hospitals.

For the first time researchers looked at the numbers of cancer patients who died within 30 days of starting chemotherapy, which indicates that the medication is the cause of death, rather than the cancer.

The study by Public Health England and Cancer Research UK found that across England around 8.4 per cent of patients with lung cancer, and 2.4 per cent of breast cancer patients died within a month.

But in some hospitals the figure was far higher. In Milton Keynes the death rate for lung cancer treatment was 50.9 per cent, although it was based on a very small number of patients.