Last year's investigation into the blood-doping ring run by a Spanish doctor led a number of optimists (I was one) to predict that the resulting clearout of big names might mean the "cleanest" Tour de France since the early 1990s, when the suspected widespread use of EPO began. Such hopes were dashed, however, after the leader, Floyd Landis, tested positive for high testosterone levels in the final days of the race. He disputes the ruling, and the 2006 Tour has no official winner.
And now the 2007 race has lost its leader, with Michael Rasmussen sacked under a cloud of suspicion - just a day after one of the favourites, Alexandr Vinokourov, tested positive for blood-doping and left the race in disgrace. All of which leaves the cycling fan shell-shocked, and the casual observer asking if they're all at it: if, in fact, there is such a thing as a "clean" bike racer.
The Tour director, Christian Prudhomme, says that it will take not reform but a "revolution" to fix the doping problem. After years of head-in-sand paralysis, the sport's governing body, the UCI, has brought in a tough testing regime, so what would a "revolution" mean, unless a root-and-branch cultural change? And that, in cycling, is not an easy thing to bring about.
It is not just that the history of substance abuse on the Tour is as old as the yellow jersey - from brandy and strychnine via amphetamines and steroids to the blood-booster EPO and human growth hormone - but that Prudhomme has to confront a mentality that reaches right down from the elite, professional end of the sport to the "weekend warriors" at the grassroots. Cycling is an almost intolerably tough sport. To take part, even at the most humble level, you need extraordinary commitment and a frankly obsessive work ethic. Your average club racer will score higher in a fitness test than a top-flight footballer.
The cruel calculus of road racing is that the difference between winning and losing can be measured in fractions of a percent in performance. Once you have entered this world, you are always looking for an edge, the tiniest advantage. In the old days, cyclists drilled out their bikes to save precious grams; now they spend hundreds of pounds on some superlight carbon-fibre widget.
And the compulsion extends from the bike to that most precious piece of equipment, the body. Cycling magazines are full of dietary advice, ads for supplements, and digests of the latest sports-science studies that show, for example, the performance-enhancing benefits of caffeine, creatine or bovine colostral protein. We devour the articles that tell us what blend of carbohydrates, protein and electrolytes works best.
All this is perfectly legal, of course - even if some products, such as creatine, and practices, such as sodium phosphate loading, may cause long-term harm. The point is that this is what mere amateurs will do to win a minor place in a nothing race. Add TV, money, fame, and what do you get but the present unhappy situation?
There are banned substances, legal supplements and a few dubious things in between, but what matters is the mindset that sees it all as belonging to a continuum of "stuff" you need to go faster. And however rock-solid your ethical stance, there will always be grey areas. I would never do blood-doping - that is, take a transfusion to boost my red-cell count; yet I am forever putting off donating blood because I know it will knock my performance for a couple of months. How ethical is that?
For cyclists to be "clean" in body means they must be almost impossibly, inhumanly, pure in heart. Can any campaign of moral re-education, however "revolutionary", succeed? Experience suggests not.
Matt Seaton