It is a hot health topic and a significant worry for patients.

Will the NHS pay for them to receive the latest treatment and would they receive it, without a problem, if only they lived somewhere else?

In the centre of this charged debate sits the Scottish Medicines Consortium (SMC), a group of individuals who decide which new treatments doctors should and should not prescribe.

Now, for the first time, the SMC has investigated how Scotland's health boards respond when they issue their advice.

At last, clear evidence; a context for distressing patient stories and industry allegations that some authorities are much slower to buy new medicines than others. Or so one might have thought.

Even the Scottish Government, in its response to a Scottish Parliament inquiry into the availability of cancer drugs, talked of the SMC probe leading to "the opportunity to monitor and address inappropriate variation in the planning and provision of drug use in cancer services".

However, if there is one question the SMC research does not answer, it is whether the much-decried postcode lottery exists.

Graphs show that the amount of money hospitals spend on new drugs for conditions such as leukaemia increases after SMC say "yes" to a treatment. Well, sometimes anyway - at least for a while, although expenditure on one lung disorder drug crashed to zero within 12 months of SMC approval.

The bottom line is that analysing who buys what drug for whom is much more complicated than one might expect. For example, while some new drugs are a significant advance on those already available, others have close competitors.

Furthermore, patients with severe forms of a condition such as rheumatoid arthritis might be referred to a different health board area for more specialist treatment.

It might look like Glasgow hospitals have stocked up on a new drug to relieve symptoms while its neighbours have not, but this could be because Glasgow is ordering for patients on its own patch and those in surrounding areas as well.

Dr Ken Paterson, chairman of the SMC, says to really compare access to a new drug in different Scottish hospitals they need to know not only how much has been dispensed, but also the postcodes of the recipients and their diagnoses.

He said: "It is virtually impossible to get global use data and there was no conceivable way we could take it down to individual patients. Until we have IT structures in secondary hospital care to get patient level information, we are not going to know about this."

Bizarrely, what the SMC research does reveal is that even when it says "no" to a medicine, its use often continues to climb.

Dr Paterson points out the numbers concerned can be small. Sure, some doctors continued to prescribe a new cardiovascular drug after it was rejected by the SMC, but the number treated was 295.

Nevertheless, he admits use of one contraceptive rose substantially, despite the SMC's rejection. He explained: "The clinical community has seen benefits from that drug that were not demonstrated to us by the company and have gone ahead and used it. That is entirely appropriate."

When the SMC blocked a new drug for kidney cancer, consultants spoke out about their disappointment.

It is too simple to say clinicians can ignore the consortium's advice and prescribe a treatment anyway.

From the personality of the doctor, to the persuasiveness of the patient, there are factors that mean access to new medicines will never be equal.

Perhaps it is no wonder the SMC also found that projections of what new treatments will cost the NHS are somewhat wide of the mark.

While the gap in good data on access to new drugs is filled with excuses, however valid, the fear that seriously ill patients are missing out on the best treatment will prevail.