The debate about co-payments and the NHS will strike some as yet another skirmish on the fringe of a long and largely fruitless battle for effective public service reform. In fact, it is about life and death, and the fundamental question of whether the NHS can survive in its current form.

For Linda O'Boyle, it comes too late. She died of bowel cancer in March after being refused the drug Cetuximab on the basis that the NHS could not afford it; nor could it allow her to make co-payments - or top-ups - towards its cost.

The same rule against co-payments has caused other patients be charged for all their NHS cancer care because they chose to pay privately for their medicines.

There is one argument against co-payments: they could, in principle, lead to two patients in adjacent beds receiving radically different treatments for the same condition because of their ability to pay. Writ large, the discrepancy would mean a two-tier system and the end of universal healthcare, free at the point of need.

In reality, such a system already exists. When the NHS fails them, better-off patients constantly find ways to buy the best care they can afford. This may not be as fair as Aneurin Bevan would have wished, but it is inevitable: the cost of medical science's latest advances has long since outstripped NHS budgets. More importantly, the iniquity of banning co-payments is worse than that of allowing them. The NHS is paid for by its patients. Where is the justice in using their taxes to subsidise the care of others, then preventing them from paying extra for their own care when they need it most? There is none. Reform of the system is welcome, but overdue.