Yes, all necessary treatment is free on the NHS - the principle is that health care in the UK is 'free at the point of use' which means that we pay for it over time through our taxes, but nobody has to pay directly to use the service.

People do have to pay for prescriptions which are made up at the pharmacist - it's not a big charge, but it was found some years ago that the NHS couldn't afford to pay for all medicines. Even with these though, you get help if you are on a low income. For all other treatment, hospital stays etc you don't pay.

It's true there has been a lot of debate lately about whether some conditions shouldn't be treated on the NHS, but this is about lifestyle issues - for example, some doctors feel seriously obese people should be encouraged to lose weight rather than being given an operation. Such restrictions aren't in place at this time, though, and in any case they would never apply to an illness like cancer.

The NHS, for all its problems, really is a brilliant institution. You can learn more about cancer treatment here.