If you are a UK resident then you are entitled to free treatment on the NHS, except where legislation says that there are charges that must be met, for example prescription charges or charges for eye tests and dental treatment. This is something that cannot be taken away from you.
There are some patients, however, that may wish to be diagnosed or to be treated privately. As a result of this fact the Department of Health published guidelines in March 2009 for patients who wish to use both NHS and private medical services.
This report states that:
You should be aware that doctors who work for the NHS are not allowed to advertise their private services to NHS patients unless you specifically ask. If you ask they will be able to tell you about any services which they provide privately, or which another doctor is able to provide that you would not be able to get on the NHS. They will also be able to tell you about any medications, which are available, privately, which are not available on the NHS.
Even if you have a private consultation and a private diagnosis you are still eligible and entitled to have your treatment on the NHS. If there is a waiting list for the treatment that you need, then your position on that list should be the same as if you had had your diagnosis on the NHS, that is to say it should be exactly the same.
If you have any complications when being dealt with privately it is usual for the private healthcare provider to deal with them unless they are an emergency. If your private healthcare provider treats you then you should probably expect to pay for them. If, for example, you have a side effect as the result of a private treatment you will have to pay for any additional treatments.
If you do decide that you wish to pay for certain parts or all of your healthcare then there are various places where you might receive this treatment. This might be from an NHS organisation that offers private services or from a private healthcare provider.