Infertility treatment in Britain remains an overwhelmingly private business. In spite of the Government’s pledge to fund one free cycle of IVF for most couples, more than 70 per cent of patients pay for their therapy, parting with an average of £3,500 for every attempt. The industry is estimated to be worth up to £500 million a year and has made some doctors very rich.

The tensions that this system creates have been highlighted by a recent General Medical Council hearing involving one of the wealthiest. Professor Ian Craft, whose fortune is valued at £25 million by the Sunday Times Rich List, was accused of overcharging for unnecessary treatments.

While he was cleared, his case has drawn attention to what the fertility economist Deborah Spar described on Wednesday as an inherent conflict at the heart of the industry. When an infertile couple approaches a private clinic, the doctor who diagnoses their problems and suggests treatments has a direct stake in the outcome of his advice. The more pricey the tests and therapies he orders, the more his business will profit financially.

Desperate patients who will go to any lengths for a chance of having a child can be told that this test or that drug might make all the difference when the evidence is weak. Women with little realistic possibility of conceiving might be encouraged — or at least, not dissuaded — from trying an expensive round of IVF that will probably be futile. There is great scope for exploitation of the vulnerable.

This is not all the doctors’ fault — there is no shortage of couples willing to press for treatments that they have been told are unlikely to work — and some checks and balances are in place. Doctors must conform to professional codes of conduct and the publication of clinics’ success rates mean that they have something to lose by overzealous recruitment of hopeless cases.

But if serious malpractice is rare — Professor Craft’s is the only recent case of its kind to reach the GMC and it was dismissed — it is clear that patients are not always given enough information to make rational decisions.

Some clinics fudge their success rates or offer averages with little relevance to patients with specific reproductive complaints. Not all make it clear that it takes an average of three cycles to make an IVF baby, and thus an outlay of a five-figure sum; nor that going private can make you ineligible for treatment on the NHS.

Price lists often exclude the cost of drugs, scans and other add-ons that can swell bills by thousands of pounds. It is not surprising that some patients feel that extra costs are foisted on them suddenly and unfairly, which they feel bound to pay because of the five-figure sums they have already invested. Many think themselves cheated, like homeowners ripped off for “completion fees” by cowboy builders who threaten to leave them with half a roof.

It would be better for all concerned if clinics were more open and honest at the outset about prognosis, the details of therapies and, above all, about likely fees. Couples would be spared unpleasant surprises and empowered to judge value for money, while doctors would be protected against complaints from angry and disappointed patients. Yet while the best clinics provide costed treatment plans already, there is no legal obligation and many do not.

The Government is reviewing the fertility laws, and it should make these plans a mandatory condition of clinics’ licences. Britain’s regulatory system is the best in the world for overseeing the science of IVF but it is powerless over the financial practices that are just as important to sound ethics.

The market can be left to decide how much patients are willing to pay — particularly if they recognise that a market is what it is — but they need full and frank information to make a reasoned choice.

Mark Henderson is the Times science correspondent