Dear Ben,
Prioritisation doesn't work so arbitarily like that in England.
We have national organisations like NICE who issue Technology Appraisal Guidance (TAG) on certain high cost drugs and medical devices, on the basis of clinical and cost effectiveness. The NHS is legally bound to fund them within 3 months of a positive NICE TAG, but will not fund them if the TAG is negative.
But there are lots of drugs and devices that NICE does not pronounce judgment on, because they don't have the capacity and resources to do so.
Then this is what happens.
You need to remember a couple of things before you read on, because it will give you the context in which we NHS Commissioners operate. Firstly the commissioners are allocated their fixed annual budget (from the beginning of April to end of March the following year). Secondly, the commissioners are statutorily bound by law not to exceed their annual budget by even an extra penny (they have to remain within their allocated resource limit). It's the classical case of Charles Dickens's Mr Micawber in David Copperfield - income 20 shillings; expenditure 19 shillings 6 pence; result happpiness/ income 20 shillings; expenditure 20 shillings 6 pence; result misery.
Let's suppose you are a consultant who wishes to use a new drug A or device B which has not been NICE'd. We consider that as a 'service development'. So, you will need to write down a business case and submit it to the commissioners for consideration during the annual prioritisation round. The annual prioritisation round takes place in December/January and all business cases have to compete against each other to be prioritised. The business cases are prioritised against a set of ethical and commissioning principles with criteria and weights (attached to each criteria) and scored. Those that score above a pre-agreed minimum score are prioritised and then sent to a group of local clinicians and commissioners who match the prioritised services against the annual budget available (in an open, transparent and 'Wednesbury' reasonable way). If your drug A does not meet the cut, the commissioners will not fund it that year.
Herein, lies the crunch. Ordinarily, if you say you won't fund it, no resident in your local population should have access to the drug/device. The principles of social justice and equity demand that it should be an 'all or none' phenomenon. Lawyers have repeatedly advised us that NHS commissioners can/should take recourse to this action. But politicians are always jittery about the dreaded 'R' word being officially bandied around. So commissioners in the NHS have agreed on a loop-hole (pretty unsatisfactory, in my opinion) to get around this system and keep the politicians happy ie through the exceptional funding route. If you want to prescribe drug A to your patient when it is not ordinarily funded by the commissioners, you will have to prove to the commissioners that your request is truly exceptional. Your request for funding is sent to an Individual Funding Request (IFR) Panel, comprised of commissioners, clinicians, the public and lay members of the Board of the Commissioning PCT, which will decide whether your exceptional funding request merits approval. All off-license/unlicensed funding requests and also funding requests for drugs/devices not approved by NICE TAG's must similarly be sent to the IFR Panel (these are the Panels that Sarah Palin et al refer to the NHS Death Panels, which, by the way, is a completely false description of these Panels).
If your funding request is refused by the Panel, you can appeal against the decision, and your appeal will be heard by an Appeals Panel, the composition of which is entirely different from the original IFR Panel. The decision of the Appeals Panel is final.
The unsuccessful patient can, however, take the commissioners to court and request a judicial review of the funding decision.
Hope you find this useful.
Regards,

Ash