The NHS could suffer from "meltdown" within the next four years due to the high cost of cancer drugs, according to a leading expert.
Professor Karol Sikora said the next generation of drugs were so expensive they could swallow half of the current NHS budget within four years.
He conceded that the drugs would keep people alive for longer, but calculated they could cost the NHS £50bn - around half the current budget, which tops £100bn.
Professor Sikora, director of Cancer Partners UK, a private provider of cancer services that works with the NHS, compiled the figures for Sky News, which is running a series looking at health treatments in the UK.
"The NHS is going to face meltdown just because of one disease, so we're going to have to restructure things for the future, look at new ways of bringing money into the health service and that is a huge political challenge," he said.
A Department of Health spokesman said: "In recent years the NHS has seen record levels of investment which will reach £110 billion by 2011. Any publicly-funded healthcare system has to make difficult decisions about what treatments are available."