ERIN HERRIN, the mother of the conjoined twins who were separated by pioneering surgery last week, has been roundly praised for offering to donate a kidney to her bereft daughter.

We are, it seems, full of admiration for parents who risk their own health in order to provide a better future for their children.

But why, then, do we condemn those who wish to donate a kidney in return for cash? After all, many would use the money to enhance the life chances of their little ones — a situation that seems identical, in all morally relevant respects, to that of Mrs Herrin.

A free market in kidneys would not only augment the wealth and autonomy of willing donors but would eliminate the chronic shortage of vital tissue. In the UK alone more than 5,500 people are on the kidney waiting list. It is estimated that 100,000 die worldwide each year while waiting in vain for a life-saving operation. It is a scandal that this mass suffering is permitted to continue when it could be eradicated with a simple change in the law.

The arguments against a free market are not merely misguided but perverse. Critics talk darkly about the wealthy jumping the queue and mutter incoherently about the exploitation of the most vulnerable. As Pope John Paul II wrote: “Buying and selling organs violates the dignity of the human person.”

The truth is precisely the reverse. The prohibition on payments to living donors has driven the market underground, making it an option available only to the rich. Desperate patients have been known to pay up to £100,000 to shady brokers who pocket the lion’s share, leaving Third World donors with a pittance. Back-street surgeons conduct transplants with scant regard to tissue typing and histocompatibility.

In a properly regulated market the donor would receive the full price for the organ and would be interviewed to ensure that they have given informed consent. A monopsony buyer, such as the NHS, would set a price so as to eliminate shortages and then make kidneys available “free at the point of use” according to clinical need.

A market in kidneys would alleviate the needless suffering of thousands while eliminating the abuses and injustices of the black market. It is the current, failed system that is a violation of human dignity.