Lord Saatchi is right to promote medical innovation, but his bill is the wrong way to do it, says a leading surgeon in The BMJ.

Michael Baum, Professor emeritus of surgery at University College London, opposes the Medical Innovation bill, saying it will "remove current safeguards and is likely to add another layer of bureaucracy that will inhibit progress. And it reflects a naive understanding of the logic of scientific discovery."

The bill, sponsored by the Conservative peer Maurice Saatchi, whose wife died from ovarian cancer, aims to give extra legal protection to doctors in England and Wales who try experimental treatments on seriously ill patients. It has just been passed by the House of Lords and will shortly be debated in the House of Commons.

But Baum argues that, contrary to Lord Saatchi's claims, medical innovation is thriving in the United Kingdom, perhaps more than anywhere. "In surgery we have witnessed phenomenal successes with organ transplantation, joint replacement, and minimally invasive procedures, he writes. And he cites "pioneering work" in the treatment of breast cancer, which he says has "contributed to a 40% fall in breast cancer mortality in the past 40 years."

"Changing the law with this bill will not accelerate innovation in cancer therapy - but it might well endanger our patients by uncontrolled experimentation," he warns.

"There is a myth that patients with terminal cancer have nothing to lose," he adds. "Hope is always important but it must not be betrayed. Freelance "innovation" will almost always bring false hope because it will rarely - vanishingly rarely - stumble on a cure."

He congratulates Lord Saatchi "for opening up this debate" but appeals for a redirection of efforts and resources "to initiate a commission that will investigate the real obstacles to progress in medical innovation, and not unintentionally provide cover for charlatans, nor muddy the waters of common law where there is now clarity."