They say all publicity is good, but I was saddened by Andrew Wall's negative review of my book (pages 28-29, 29 April). Ten years ago, when he was chief executive of Bath health authority, I was inspired by his openness in trying to reconcile his beliefs with the reforms he had to administer. I'm not sure why he is now so defensive, but Trust Me, I'm a Doctor is certainly not written for laughs.

As Pamela Charlwood, chief executive of Avon HA, observed: 'I think it would be wrong to say I have been 'enjoying' the book, because the messages are so salutary and sobering - and uncomfortably true - but I have certainly been appreciating it.'

The essence of my argument is that unacceptable things happen in medicine, from the student bar to the reading room of the Royal College of Surgeons. They may involve a small minority of doctors, but they are also well known yet almost never acted on. Instead, they get displaced into black humour. This may be a coping mechanism, but more often it disguises and dismisses poor performance. Hence, units become known as the 'Killing Fields' and surgeons are dubbed 'Butcher'. But no one stops them.

Wall may feel that such insights are not suitable for the public, but my involvement in exposing the Bristol case and others has taught me that bad practice thrives in secrecy. If we don't come clean about the inadequacies of medical training and the NHS, how can we address them? Those on the inside know there are unacceptable variations in quality in every specialty, and that it really does matter where you get treatment. Why should the public be denied that information?

Wall's charge of opportunism is unfair, since I have been toeing the same line publicly for 10 years. He may not take Private Eye seriously, but as its medical correspondent I have been asked to give evidence at the Bristol inquiry, and a campaign started in the Eye last August, calling for all babies born with biliary atresia to be treated in specialist liver centres, now has the full support of the Royal College of Surgeons and the Department of Health. Of course, any column is only as good as its sources and, four years after Bristol, the fact that doctors still don't trust their colleagues and managers enough to go through the correct channels depresses me even more than Wall's review.

Dr Phil Hammond

GP, lecturer, writer and broadcaster