I place a great deal of importance upon the integrity and reliability of the source of critical information, particularly when it may impact upon my health and wellbeing.

Years of scientific training, where one is taught to criticize and question all statements, don't wear off easily. This tends to become a bit of a curse, whereby I am suspicious and slow to accept so many widely touted miracle cure claims, emanating from myriads of sources; however, I can maintain a scientifically agnostic attitude, whereby I don't necessarily believe, but am open to be shown the evidence.

However, as any healer or successful practitioner will attest, a crucial component to any intervention is an intent by the physician, the scientist, the healer, of the highest integrity. In the present-day world of commercial markets, where profits sometimes appear to be of paramount importance, surely it would still be anathema to most health and scientific professionals to have as their goal deliberate harm or evil.

I will never forget the day, almost 20 years ago, when this subject came up in the corporate microbiological scientific group (attempting to clone nitrogen fixing genes in bacteria) where I was working. I posed the hypothetical question to my manager, who had a graduate degree in microbiology, about whether, if our company were to change our project from agricultural research to, say biological warfare, he would take the job and work in biological warfare. To my utter amazement, he easily replied yes, that if he didn't do the work, someone else would.

Now I am not an incredibly jingoistic person, and I don't go around boasting that I would die rather than commit certain acts; however, if there was any scientific work that I would rather die than be a part of, it would be for the evils of trying to kill perhaps tens of millions of people.

I think that it is terribly important that all people hold high moral standards, and most importantly, those people whose work has such crucial impact on our lives.

Fast forward to the present day, where, in part because of the BSE and vCJD crisis, not to mention past food poisoning and ongoing vaccination scares, we have all been shaken in our beliefs about the reliability of official information.

As a scientist, I realize that it is virtually impossible for any person to know all the answers; I just wish that most public figures had the humility to admit that they don't know. The great scientific figures for which I have the greatest respect are those who always preface their remarks stating their huge ignorance of their field.

I was therefore gobsmacked when, in The Guardian on Saturday 28 October 2000, right smack in the middle of a huge news feature entitled Civil servants, scientists and the road to the truth – Science on the rack (a double page spread all about BSE, mobile phones, smoking and other potential horror stories) was placed a huge advert (larger than 3 A4 pages) for Marlboro cigarettes!

Within the text of this feature was written the following "British scientists have warned us that smoking kills since the 1950s, but people are still buying cigarettes, getting lung cancer, and dying."

So, although it is an accepted fact that smoking kills in huge numbers, and even in the middle of an article about a crisis of confidence in scientific reporting, someone at The Guardian had the insensitivity to run an advertisement for a substance that kills. What this tells me about The Guardian is that when push comes to shove, revenue from advertising takes precedence over any squeamish moral pangs about the ethics of promoting smoking. I am not attempting to single out The Guardian – it just happened to be the newspaper I was reading that day.

Furthermore, how can the former Minister of Health (Kenneth Clarke), responsible for the health of the nation, occupy in good conscience, the executive position of Deputy Chairman of British American Tobacco (BAT)?

I am frequently asked for advice regarding treatment programmes, courses or even products within the very wide remit of Complementary Medicine. Although I probably read and see and have experienced more in these fields than many, I have become exquisitely aware of how different people's needs, beliefs and situations are.

I am happy to point individuals toward what I hope are reliable sources of information, and perhaps to suggest that they seek professional assistance in exploring their options; but I know that in the end, everyone needs to do what they think is right for them. Being suspicious and critical may lead to saving your life.