The Spanish judge dealing with the compelling and sometimes bizarre evidence of the systematic doping of a long list of prominent sportsmen, including almost inevitably many cyclists, may have decided that the evidence was insufficient to warrant further examination, but the Operacion Puerto affair continues to send shock waves around the world of professional cycling.

Jan Ullrich is the only big-name client of Dr Eufemiano Fuentes to have lost his livelihood as a result of Puerto. I suspect that this may be partly the result of declining motivation on the German’s part, though he also has the dubious distinction of being the only rider so far to be forensically linked to specific blood bags.

Many Spanish riders, including Paco Mancebo and Oscar Sevilla, have stepped down a division, though still race as professionals, and it is widely believed that they may be on borrowed time as the countdown to a more thorough re-examination of the evidence continues. The Prosecutor’s appeal against the judge’s decision is due to be heard on the eve of this year’s Tour De France, and already we are seeing signs that the sport is preparing itself for the horrible truths that may yet be unleashed.

The latest development came on Friday of last week, and it is one that has massive implications for Italian rider Ivan Basso, the heir to Lance Armstrong’s throne. Christian Prudhomme, chief of the body (ASO) that organises and selects the teams and riders for many top Pro Tour races including the Tour De France, announced that any rider implicated by Puerto would not be welcome at this year’s Tour.

Perhaps mindful of the need to avoid a re-run of last year’s Landis debacle – incredibly we still don’t actually know who the winner of the race is – Prudhomme is keen to tread cautiously. Basso would almost certainly have won the Tour last year, and I suspect that despite not showing much form so far this season would, by virtue of his undoubted class on a bike, have been favourite for the 2007 edition.

Whilst I’m all for atonement and second chances in life, Basso’s own response to Puerto doesn’t elicit much sympathy. Surrounding himself with a stonewall of denials, and a legal team not seen since the days of Tyler Hamilton, Basso has steadfastly refused to take the DNA test that would clear his name.