One Friday evening in the winter of 2009, I ended a 20-year affiliation with a college of the University of London, lugging three boxes of personal possessions and a bucket containing 12 tropical fish from my emptied office. In the face of looming redundancy, brought on by my failure to contribute adequately to my department's last Research Assessment Exercise submission, I jumped before I was pushed. I left with a compromise agreement and a lot of thoughts about how my career, initially as a reasonably successful scientist, had come to such a sticky end. My story has useful lessons in it, some of which are exclusive to scientific research but some of which reflect, I think, the experience of women in academia.

I was a ferociously smart child who attended a mediocre state comprehensive school, scraping sufficiently good A-level grades to get myself into the University of Bristol, at the start of the 1980s, to read biochemistry. I flourished at Bristol, discovering fellow smart-arses who were more at home with science than the world of glam rock that had obsessed so many of my former schoolmates. I got the top first in my year and applied, with a mixture of terror and chutzpah, for a Ph.D. at the Medical Research Council Laboratory of Molecular Biology (LMB) in Cambridge, which was then at the pinnacle of science in the United Kingdom; seven scientists working there during my time have gone on to win Nobel Prizes.

Every scientist needs someone in a position of power who has faith in his or her abilities, to provide advice and do a bit of trumpet-blowing on his or her behalf.

Working among the vestiges of Fred Sanger's empire, I sequenced the DNA and mapped the mRNA transcripts of a segment of the human cytomegalovirus genome and discovered the thrill of working all hours in the company of like-minded science addicts. Although it was a bit frightening being grilled on one's experiments by people whose brains were the size of whole solar systems, I graduated with a solid Ph.D. from LMB after 3 years and then went for postdoctoral work in San Francisco with J. Michael Bishop of the University of California, San Francisco. Mike advised me to work on the Myb proto-oncogene, whose overexpression is associated with autoimmune diseases and malignancies. By a combination of my luck and his judgment, I ended up with a nice Cell paper showing that Myb is a transcription factor. With a pretty good curriculum vitae in hand, I came home in 1989 -- the same year Mike won a Nobel Prize -- to a tenure-track job, running my own research lab at a University of London institute, where I remained until the sad demise of my career.

So, what went wrong? There are a great many alluring things about an academic scientist's lifestyle that are simultaneously liberating and dangerous. The best of these are that you can work pretty much whenever you like, on whatever is interesting; the flip side is that "whenever you like" often translates into "all the time," and "interesting" is a matter of who you're talking to. For the first 5 years or so, I loved the freedom of being a scientist in what was touted as a meritocracy. I did work very hard, and I got somewhere, showing that Myb had an important function in the development of white blood cells.

However, I was always hampered by self-doubt. My initial conviction -- essential for anyone who wants to make it as a scientist -- that I could really make a difference, maybe even win a few prizes and get famous, eroded when I realized that my brain was simply not wired like those of the phalanx of Nobelists I met over the years; I was never going to be original enough to be a star. This early realization, combined with a deep-seated lack of self-confidence, meant that I was useless at self-promotion and networking. I would go to conferences and hide in corners, never daring to talk to the speakers and the big shots. I never managed, as an infinitely more successful friend put it, "to piss in all the right places."

My loss of belief in my own potential was the first step toward where I am today. Once I had decided I would never be shaking hands with royalty in Stockholm, I downgraded my career expectations drastically, in a way that fellow failed perfectionists may recognize. I focused on more mundane goals, such as getting a permanent job in the U.K. system. I got tenure, and after about 10 years of running my lab, my science declined. I never felt I could take on the big players in the hot topics, so I found myself a secure little niche far from the madding crowds. I went on working on the Myb protein in a small and insignificant field populated by rather nice people with whom it was possible to have fun as well as do science. My obsession with my work declined as normal life seeped in: I got married, learned to ride horses and play the cello, looked after aging parents, and nixed all hope of redemption by having two children in my late 30s and realizing they were far more interesting than what I was doing at work. By the time I carted my boxes and fish out of the building, I was working a standard 37.5-hour week, which simply does not suffice if you want to stay competitive as a scientist. And I was bored, terribly bored.

What could I have done to check my descent into mediocrity? I should have put aside my fears of looking dumb and got on with the networking stuff anyway. And -- very importantly -- I should have found myself a mentor. Every scientist needs someone in a position of power who has faith in his or her abilities, to provide advice and do a bit of trumpet-blowing on his or her behalf. I should have taken more scientific risks, gone for bigger stakes, and thought harder about direction. Finally, I should have followed my instincts and quit my job before it quit me -- but I was hampered by an exaggerated terror of being labeled a failure. (In fact, none of my friends and family seems to care a hoot about my fall from grace, and of course I should have known that all along.)

And what of the system? It failed too, I think. Scientists are judged almost entirely on research output, measured by papers published in the most prominent journals, and grants are not awarded unless your work is competitive at the highest level. Trying to run a lab full time with small children at home is very likely to result in a drop in research productivity or quality, and yet little allowance is made for those of us, mostly women, who find ourselves in this situation. I believe I could have run my lab very successfully if I had been permitted to job-share with a close female colleague, also with two young children. Between us, we could have covered all the bases, and perhaps as a team we would have retained our competitive edge and hence our enthusiasm. This just does not happen in the male-oriented world of science in which, traditionally, dogs are keen to dine on dogs rather than share the bone between them, so to speak.

I know that many readers will think that I had it coming: In the long run, I didn't work hard enough and I was lucky to get out with anything at all. In my darker moments, I entirely agree with them, but simultaneously I feel sad for the idealistic young woman I once was. Part of my speech welcoming incoming Ph.D. students at my institute was to remind them that academic science is a vocational career. It really was that for me when I started, and although I've started a new life as a science writer, and I'm loving it, a small part of me will always miss the excitement of life in the lab -- that hopeful voyage into the unknown where sometimes, just sometimes, you look at a result and realize you've found something nobody else has ever seen before.